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SwizzyMan
07-17-2016, 05:19 PM
just picked up this nice CTC-4 director down in West Palm. The set has a big history and has been heavily modified. This set originally came from Connecticut. It was acquired by its previous owner (he was a repairman) when a customer decided that the set was too expensive to get repaired and they left it. It eventually moved down here to Florida. The previous owner was an experienced Ham radio operator. I was invited to take a look around his house while we were picking the set up, his house was full of receivers and a couple FM transmitters he built himself with many other pieces of tube equipment. I originally heard about this set through my wanted ad in the classifieds here. The original price was $6000 BIN and $3000 to bid on it. Eventually, it made its way to $500 after I offered $500 for it. The first thing that I noticed when i saw it on ebay was that it had a glass 21FBP22 instead of the original 21AXP22 crt. This didnt bother me much at all. While it may decrease its value, the FB will have a much better chance of surviving all these years without leaking. I was able to test the CRT today and the results were a bit discouraging, the cutoff on almost all the guns was just barely under the box on my CR-31A, and to make matters even more confusing each gun tested fine for a few seconds on the tester, but then the needle starts swinging erratically and upward. I thought I read somewhere that these results may indicate a gassy tube, but this doesnt make any sense since I can get a full raster, but the tube seems kind of dim and the red color seems to the least bright of the three colors. I'm not sure if I should zap the three guns with a rejuve or what. I ran the set for about five minutes monitoring the current draw just so I could get a baseline. I got a decent black and white picture, but when I turned the color on I got a lot of interference in the form of small streaking horizontal lines. I also noticed the colors are pretty rough with no signs of light blue and pretty dim reds. At the end of the five minute run I heard a loud pop (sounded like a firecracker).Current draw stayed fine. I immediately shut the set down. I think a paper cap finally gave out causing the loud pop. This is going to be a long project , but I think I can handle it.

SwizzyMan
07-17-2016, 05:21 PM
More photos

wiseguy
07-17-2016, 05:40 PM
you should Discharge the HV from the CRT completely before testing on a CR-31, this would cause Erratic Testing, the pop you heard could have been a HV discharge to chassis Ground since its been modified for a newer tube, I went thru this on my ctc-4 before the CRT got rebuilt when hawkeye was in business, there is also some mods in the Gun Drive Circuit to make these newer tubes "run" correctly, color Temp is a bit different
Good Luck!

old_coot88
07-17-2016, 06:13 PM
The loud pop could easily have been a HV arc from the anode button to the shield (where somebody has made a big cutout in the shield). In fact, in your 5th photo there's what looks like an arc track from the button to the shield.

"rejuvving" the jug should be the absolute last resort.

Phil Nelson
07-17-2016, 08:26 PM
Definitely do not rejuvenate the CRT at this point. Too easy to kill the tube, and what you're seeing on the screen may be normal for a CTC-4 that's chock full of bad caps. A working television will tell you more about a CRT's condition than any tester.

I agree with old_coot88, that pop sound could be arcing, and the cutout in the CRT metal retaining ring is an obvious place to look. If you run the TV briefly in a completely dark room, you might even see the zap occur along that dark track seen in the photo.

When I installed a glass CRT in my set, I made a smaller cutout in the ring, but I also covered the nearby edges with cambric insulating tape rated for 90KV. More about all that in:

http://antiqueradio.org/RCACTC-4ColorTelevision.htm

You are right to think of this as a long term project. Be patient and it will all get done. CTC-4s don't come along very often, so enjoy working with this one while you can.

Have fun!

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

P.S. What's in the little metal project box? Looks like a relay and a tube on top . . . ?

SwizzyMan
07-17-2016, 08:38 PM
Definitely do not rejuvenate the CRT at this point. Too easy to kill the tube, and what you're seeing on the screen may be normal for a CTC-4 that's chock full of bad caps. A working television will tell you more about a CRT's condition than any tester.

I agree with old_coot88, that pop sound could be arcing, and the cutout in the CRT metal retaining ring is an obvious place to look. If you run the TV briefly in a completely dark room, you might even see the zap occur along that dark track seen in the photo.

When I installed a glass CRT in my set, I made a smaller cutout in the ring, but I also covered the nearby edges with cambric insulating tape rated for 90KV. More about all that in:

http://antiqueradio.org/RCACTC-4ColorTelevision.htm

You are right to think of this as a long term project. Be patient and it will all get done. CTC-4s don't come along very often, so enjoy working with this one while you can.

Have fun!

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

P.S. What's in the little metal project box? Looks like a relay and a tube on top . . . ?

Thanks Phil! I'll try and keep watch on that area suspect to arcing. The little project box is actually a soft start module. It lets the tubes fully heat up before applying any voltage to them. The same concept is shared on your CTC-7, but this was one of the modifications the previous owner installed. I think its pretty nifty! :D

SwizzyMan
07-17-2016, 09:31 PM
Cant tell if this is a HOT cathode current meter or what. I dont think it is since the meter only has a range of 10 MA and normal cathode current is atleast 100MA.

Electronic M
07-17-2016, 10:38 PM
Cant tell if this is a HOT cathode current meter or what. I dont think it is since the meter only has a range of 10 MA and normal cathode current is atleast 100MA.

It could be a cathode current meter with the appropriate shunt resistance in parallel with it to scale the current it receives to the appropriate range...

old_coot88
07-17-2016, 10:57 PM
Cant tell if this is a HOT cathode current meter or what. I dont think it is since the meter only has a range of 10 MA...
That meter is one milliamp full-scale. So it's probably wired to measure the HV regulator current. If it's measuring H.out cathode current, it'll have a low value shunt across it.
...and normal HOT cathode current is at least 100MA.
Normal H.out cathode is closer to 200 ma.

SwizzyMan
07-18-2016, 08:11 PM
I wonder if the CTC-4 has those pesky HV issues like the CTC-5 does? I really hated dealing with that in my 5. And how is its performance? Hopefully better than my 5 too.

miniman82
07-18-2016, 08:35 PM
5 is the only one with weak HV, you won't have any trouble getting a full 24/25 KV out of this set.

SwizzyMan
07-18-2016, 10:00 PM
I was doing another current monitoring power up to keep an eye on the possible arcing area from crt to yoke shroud/housing. I discovered something very interesting and possibly damning. There is a strange orange almost neon-like discharge between the very edge of the internal coating to the shadow mask assembly im assuming in the crt. Now I dont suspect this to be oxygen molecules since the color of the discharge is orange not purple, but could this mean my CRT is in trouble? I don't think the tube is gassy since I can still get a nice, bright and full raster on the screen. I've noticed the glow kind of likes to jump around like some neon bulbs do (like electricity in a decorative neon flame bulb trying to find the path of least resistance). This is concerning me since I have never EVER seen anything like this. Your thoughts?

ohohyodafarted
07-19-2016, 12:58 AM
Contrats! Appears to be a rather nice set condition wise. Although, I feel it's shameful that it has been butchered with an all glass tube. Just my personal opinion; as I feel that the real reason to own an early color set is to have the original rare metal crt and be able to see what an actual color picture looked like back in the day with a 21AX.

BTW: if you should decide to convert this back to the correct 21AX crt, I have a purity ring and the plastic insulation shroud from a ctc4 I would be willing to sell.

miniman82
07-19-2016, 07:14 PM
Same here, came on a spare jug I bought and I don't need it. Got the metal parts too, they aren't hacked.

SwizzyMan
07-19-2016, 07:21 PM
As soon as I get some money. I'm buying an ax if I can even find one. I really wish I had an ax for this set. But can anyone answer my question on the reasons for the orange discharge in my glass 21FB?

miniman82
07-19-2016, 07:26 PM
Who cares, it makes an image.

Phil Nelson
07-19-2016, 07:47 PM
I'd love to find a 21AXP22 for my CTC-4, but they don't grow on trees. Meanwhile, a glass CRT lets me watch the set. Without viewing two CTC-4s side by side (one with 21AX, the other with glass), I'm not sure my uneducated eye could tell one from the other, anyhow.

Sorry, I don't have a good guess about the orange discharge inside your CRT. What's the condition of the CRT's aquadag coating? All in good shape and securely connected to ground? Does the dancing glow move in concert with arcing sounds? Or is completely independent?

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

timmy
07-19-2016, 07:57 PM
Is there a ground strap on the bracket that holds the crt ?
Sorry it was mentioned already by Phil Nelson .

SwizzyMan
07-19-2016, 08:00 PM
I'd love to find a 21AXP22 for my CTC-4, but they don't grow on trees. Meanwhile, a glass CRT lets me watch the set. Without viewing two CTC-4s side by side (one with 21AX, the other with glass), I'm not sure my uneducated eye could tell one from the other, anyhow.

Sorry, I don't have a good guess about the orange discharge inside your CRT. What's the condition of the CRT's aquadag coating? All in good shape and securely connected to ground? Does the dancing glow move in concert with arcing sounds? Or is completely independent?

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Dag is perfect.Dusty but in nice shape. The dancing orange glow is completely independent. It only occurs on the lower areas and sometime the top areas at the left side of the CRT. While I'm no longer concerned about my CRTs health I am still wondering what this is or if it does mean trouble. I will also mention that the external graphite coating is properly grounded.

jr_tech
07-19-2016, 08:37 PM
But can anyone answer my question on the reasons for the orange discharge in my glass 21FB?

Just a very wild guess... perhaps some red phosphor from the photo-deposition screen process did not get cleaned completely off of the panel skirt. and is being excited by secondary electrons emitted from the shadow mask. :scratch2:

jr

miniman82
07-19-2016, 08:58 PM
Shouldn't be possible, the shadow mask is spot welded to a frame which has a lip on it that extends back towards the electron gun specifically to prevent stray electrons.

Phil Nelson
07-19-2016, 09:13 PM
One last question: does the display on the screen face change in any way when the orange glow is dancing? I don't have a theory about what it is -- just curious.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
07-19-2016, 09:19 PM
One last question: does the display on the screen face change in any way when the orange glow is dancing? I don't have a theory about what it is -- just curious.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html
I can't say the picture changes at all. Absolutely nothing out the ordinary with the screen brightness.

MRX37
07-20-2016, 02:33 PM
Tube's probably fine, just a bit weird.

Also the guns might "wake up" if left to run for awhile.

jr_tech
07-20-2016, 07:41 PM
Shouldn't be possible, the shadow mask is spot welded to a frame which has a lip on it that extends back towards the electron gun specifically to prevent stray electrons.

Interesting, I haver broken open a 21FBP22 so have not seen this lip... how far back does it go... far enough to cover the frit bead? Perhaps the frit bead is aluminized or dagged over to prevent charging and or secondary emission, or the lip perhaps covers it ? :scratch2:

just curious,

jr

SwizzyMan
07-20-2016, 07:42 PM
Let the CRT cook for an hour. It came right up. Full steam ahead with the restoration. Already have good color picture but a lot of interference.

MRX37
07-20-2016, 08:41 PM
Well heck, you're already 90% there. Probably just needs a good recap and it'll be good to go.

SwizzyMan
07-20-2016, 09:29 PM
Here is what I am working with. Heavy interference and bad purity.

Electronic M
07-20-2016, 09:41 PM
Looks like bad alignment to me. If you turn down the color to 0, then adjust the fine tuning for best monochrome odds are a lot of that smearing/ringing will go away, and if you then turn the color back up you will not get near as good a color picture at that fine tune setting.

The alignment on my CTC-4 is total crap (thus why I put it to the side)...Color, monochrome, and sound all are at their best at different fine tune settings and there is NO compromise setting that allows two to be even decent simultaneously.

jr_tech
07-20-2016, 10:15 PM
Here is what I am working with. Heavy interference and bad purity.

How is the dag on the outside of the CRT grounded? Perhaps there is some arcing that is causing the interference? A fair amount of surface area is needed where the ground connection is made to the dag. Learned this back in my "poor starving young engineer days" where all that we had for a color tv was a small group of 4s that were patched together well enough to sorta work on a rotating basis. One of mine got necked (sliding closet door accident) and all that I could get was a rebuilt 21FBP22. It took a bit of effort to get the jug grounded well enough to stop the interference streaks in the picture.

jr

old_tv_nut
07-20-2016, 10:17 PM
The color bars have an obvious sound beat - so the sound trapping is definitely not right at this fine tuning setting. Does the interference dance to the audio? (hard to tell from a still shot)

miniman82
07-21-2016, 12:26 AM
Interesting, I haver broken open a 21FBP22 so have not seen this lip... how far back does it go... far enough to cover the frit bead? Perhaps the frit bead is aluminized or dagged over to prevent charging and or secondary emission, or the lip perhaps covers it?

Been a while since I have looked at it, but on a guess probably 3/4" or a full 1"? Something like that. This particular mask and frame assembly was from an AXP that got turned into a picture frame, but I don't think they changed anything about its construction in later tubes. Don't remember where I read about it either, but I know that the lip in there is to prevent stray electrons from reaching the screen and lighting up any of the phosphor dots.

SwizzyMan
07-21-2016, 09:21 AM
Here's a video of what it looked like back in December of 2015. I guess alignment can go that far off after sitting dormant for 8 months? https://www.youtube.com/watch?v=O15e4R8jr8k

DaveWM
07-21-2016, 10:31 AM
alignment does not go off as far as the coils are concerned unless there has been screw driver drift. I would look somewhere else. Clearly the beat pattern is prob from miss tuning of the fine tune adjustment. the other is some kind of interference.

I assume you are using some kind of RF devise for the signal, is that the same as the early example? If RF try a different channel if that is an option. Assuming you have matching transformers and good quality cable for feeding the signal.

SwizzyMan
07-21-2016, 10:53 AM
alignment does not go off as far as the coils are concerned unless there has been screw driver drift. I would look somewhere else. Clearly the beat pattern is prob from miss tuning of the fine tune adjustment. the other is some kind of interference.

I assume you are using some kind of RF devise for the signal, is that the same as the early example? If RF try a different channel if that is an option. Assuming you have matching transformers and good quality cable for feeding the signal.
I'm using a BT modulator. It has that horrible hum when the modulation is too high, but my other two roundies don't have the overmodulation hum in their speakers and for some reason only the 4 is humming. The fine tuning knob only turns about an eighth of a turn before I lose sync. It was originally hooked up to a dtv converter box.

andy
07-21-2016, 11:00 AM
Alignment doesn't just go off by itself, so I would start looking for some kind of component failure. Verify any work you did on the sets since it last worked better. It's easy to make a mistake. Some things I've run into are accidental shorts in a tightly packed point to point chassis like this, or breaking one the the fine wires on a coil or transformer when it connects to the terminal.

old_tv_nut
07-21-2016, 11:07 AM
Sometimes it is possible for the fine tuning to be so far off that the tuner is recieving while set on the next channel and/or tuned to the wrong sideband of a simple modulator.
If you are using channel 3 on the TV, try channel 4 or vice versa. If your modulator is versatile, try both one channel up and one channel down.

DaveWM
07-21-2016, 11:12 AM
baluns, terminations, OTA on that channel, connections, etc...
I had one with an intermittent balun in the tuner that gave me issues once.

old_coot88
07-21-2016, 12:11 PM
Just for the heck of it, try subbing the last IF tube. Ringing/smearing in the luma is a not-uncommon problem caused by the last IF tube, even tho the tube tests 'good' on a tester.

SwizzyMan
07-21-2016, 01:43 PM
I'll switch to channel 4 and sub the 3rd IF 6AN8. Don't see why 8 months would totally mess this thing up.

DaveWM
07-21-2016, 03:10 PM
was nothing done to it in those 8 months?

Electronic M
07-21-2016, 03:45 PM
Some things I've run into are accidental shorts in a tightly packed point to point chassis like this, or breaking one the the fine wires on a coil or transformer when it connects to the terminal.

CTC-4s have PCB IF, sound, and parts of other stages.

SwizzyMan
07-21-2016, 05:44 PM
changed the channel to 4 and subbed the 3rd IF tube. Not much difference, but now I can get a pretty clear b&w picture, but when I turn on the color all the interference shows up. Once I get rid of all color the interference goes away. The fine tuning knob still has only an eighth of a turn before I lose sync, but about half way through the 1/8 turn clockwise the color starts to fade but does not disappear and the overmodulation hum gets louder.

SwizzyMan
07-21-2016, 06:13 PM
I must also note that none of the tubes are shielded. I'm sure that isnt helping my interference problem anyways. And Dave, according to the previous owners the set hasn't been powered up since last December.

andy
07-21-2016, 06:52 PM
changed the channel to 4 and subbed the 3rd IF tube. Not much difference, but now I can get a pretty clear b&w picture, but when I turn on the color all the interference shows up. Once I get rid of all color the interference goes away. The fine tuning knob still has only an eighth of a turn before I lose sync, but about half way through the 1/8 turn clockwise the color starts to fade but does not disappear and the overmodulation hum gets louder.


That's interesting, the CTC4 I'm restoring also has a huge amount of chroma noise, but produces a decent B&W picture. So far, I've recapped it, and changed a lot of off value resistors. I've done a few of the simpler adjustments, but not a full alignment.

Electronic M
07-21-2016, 07:44 PM
I must also note that none of the tubes are shielded. I'm sure that isnt helping my interference problem anyways. And Dave, according to the previous owners the set hasn't been powered up since last December.

The IF tubes and a few others are supposed to have shields....I recommend finding some shields before messing with it too much.

Hagstar
07-21-2016, 08:24 PM
I must STRONGLY agree about the shields. My CTC4 is extremely fussy about some of them being grounded well OR I get weird diagonal lines or loud humming.

John H.

SwizzyMan
07-21-2016, 09:33 PM
Roger that. Most of them are in a separate box that the set came with

jstout66
07-22-2016, 06:42 AM
It has to be something simple, since it worked 8 months ago. I'd agree with what Andy and Electronic M said.... Put the shields back. Also, I wouldn't attempt an alignment. They NEVER go out of alignment on their own, unless it's a component failure or someone in the past has been screwing around, and 9 times out of 10, it was somebody that got happy with a set of Radio Shack "diddle sticks". I was also reading some earlier posts. I wouldn't worry too much about the caps. If it was a repair tech that had it in the past, I'd assume it's been re-capped. Maybe I missed it in a prior post, but have you looked yet to verify? I also wouldn't worry too much about the tube conversion job. It looks like it was done long ago, and if it wasn't done right, those problems would have surfaced eons ago. It will be something so simple, you'll probably smack yourself on the head when you figure it out. :)

DavGoodlin
07-22-2016, 08:48 AM
What generator setup would you be using for an alignment?

I have two very original and crispy CTC16 chassis' I must repair for a combo owner, so I will be looking at this issue for sure.

Usually the adjacent sound reject adjustment (before the first IF) and sound reject (at the third IF stages need to be dialed in first.
Not sure of a CTC4 swizzy, but start there - it could be all you need to tweak.

miniman82
07-22-2016, 12:19 PM
I can do alignments Dave, I have a full setup here and I'm only a state away from you. Just did a CTC-9 not long ago.

Phil Nelson
07-22-2016, 03:40 PM
I'm not clear on the restoration status of this set. Did the previous owner do some minimal "make it work" repair years ago? Did he do a full restoration? Something in between?

If the original electrolytics have not been replaced -- or at least checked! -- I would not feel safe running this set for prolonged periods.

Forget alignment for the moment. TVs don't un-align themselves by sitting around. Install a full set of tube shields and see if they help.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
07-22-2016, 04:13 PM
I'm not clear on the restoration status of this set. Did the previous owner do some minimal "make it work" repair years ago? Did he do a full restoration? Something in between?

If the original electrolytics have not been replaced -- or at least checked! -- I would not feel safe running this set for prolonged periods.

Forget alignment for the moment. TVs don't un-align themselves by sitting around. Install a full set of tube shields and see if they help.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

The previous owner was a TV repairman. I was told he would fix the set if anything was acting up with it. He never did a full restoration, he just kept the set alive. I can see some wax caps that are still on the boards and in other places visible on the top side of the chassis.

SwizzyMan
07-22-2016, 04:55 PM
Putting shields on the tubes helped a whole lot. There is still some interference with the color picture but not the B&W picture. Colors are off in some settings and text is difficult to make out. I used my CTC-7 for a picture comparison (hope you dont mind me riding your coattails with that panther lamp Phil! :D). Please ignore the moire effect on the 4 that isnt visible under normal vision nor is it that distorted looking. There is still some beat frequency but that's about it for interference.

MRX37
07-22-2016, 06:11 PM
Looks like you've gone from 90 to 95% there, unless you want to recap the set.

SwizzyMan
07-22-2016, 09:02 PM
Looks like you've gone from 90 to 95% there, unless you want to recap the set.

Seems like I might have to recap to ensure its longevity.

miniman82
07-22-2016, 09:12 PM
Seems like the color was up too far in those shots, but it's tough to get representational shots off the screen. Make sure you test all the tubes too, mine had a pair of 6Cl6's that tested nearly dead but it still worked.

Phil Nelson
07-23-2016, 01:47 AM
Hey, the more panthers the better!

That picture stands up pretty nicely against the CTC-7. This set is already working so well, I'd be inclined to use a light hand with further work. Do what you think necessary to make it safe & enjoyable to play, but don't disturb things (convergence & alignment, for instance) unnecessarily.

Phil Nelson

SwizzyMan
07-27-2016, 08:15 AM
I'm going to replace all filter caps, all electrolytics, and out of tolerance resistors. Going to sub the two 6CL6 in the color circuit to see if I get any difference in my light blue colors not really showing up.

Hagstar
07-27-2016, 04:16 PM
With my CTC4 what I did was replace every wax and 'lytic cap before applying power even once. Too much irreplaceable stuff in there to risk a shorted paper cap taking it out. Then I ended up replacing a few brown dip caps (installed in the 70s I'd guess) as well.

Electronic M
07-27-2016, 04:30 PM
The caps to be wary of would be PS lytics, sweep/deflection stage caps (where the unobtainium lurks), and since it is not working quite right RF/IF/color stage caps.

SwizzyMan
07-27-2016, 06:04 PM
Subbed the two 6CL6's. Powered it up slowly. The colors are spot on now and I now have a nice picture. Still a bit of interference and small letters are hard to read. Needs some dynamic convergence, static conv is good. Set isnt drawing a lot of current. Only about 2.5 amps according to the PR57. Operating at a full 375 watts the set would draw 3.2 amps but it isnt even near that at 115 volts. I do still plan to electronically restore this set just trying to get a base-line on what Im dealing with. Ignore the Moire effects. The blue screen is turned up a bit too high in these photos.

Electronic M
07-27-2016, 06:22 PM
I think you want to optimize focus, increase contrast, and reduce color level.

Phil Nelson
07-27-2016, 09:49 PM
Amen to what Electronic M said.

Also, speaking as one who has served hard time grinding his teeth over dynamic convergence, I'd try all other adjustments & tweaks before you mess with that. And if you're convinced it's necessary, read the instructions carefully and perform the steps in order.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

MRX37
07-28-2016, 09:46 AM
http://www.videokarma.org/attachment.php?attachmentid=191973&d=1469657021

"Ahhhhh! Patrick! The screen looks like a fishbowl and I see wavy lines everywhere!"

dieseljeep
07-28-2016, 10:24 AM
http://www.videokarma.org/attachment.php?attachmentid=191973&d=1469657021

"Ahhhhh! Patrick! The screen looks like a fishbowl and I see wavy lines everywhere!"

I looks like IF strip ringing, by either a bad tube or loose connection. I hope, it's not an alignment issue.
Is the CTC4, the only RCA set, that used the 6AZ8 tube. :scratch2:
My Knight-kit R100 receiver uses two of them.

SwizzyMan
07-28-2016, 10:26 AM
I looks like IF strip ringing, by either a bad tube or loose connection. I hope, it's not an alignment issue.
Is the CTC4, the only RCA set, that used the 6AZ8 tube. :scratch2:
My Knight-kit R100 receiver uses two of them.

I sure hope it isnt alignment. I'll take a look

SwizzyMan
07-28-2016, 11:31 AM
Starting to think this may need an audio alignment. I can fine tune in a clear color picture, but the sound isnt there just the loud buzz of the modulation. When i turn the fine tuning knob to receive sound, the picture gets a lot of interference and the swirly lines show up. In other words the audio is not at the same tuning position as the clear picture signal. I suspect an audio alignment may be necessary.

miniman82
07-28-2016, 03:06 PM
Hope it's not the same issue mine has, the audio went totally kaput on it one day and I think the IF can has an open winding or something. I can twiddle any slug I want, all it does is sound like a radio not tuned to any station. Gotta dig back into that thing at some point.

Electronic M
07-28-2016, 05:10 PM
Hope it's not the same issue mine has, the audio went totally kaput on it one day and I think the IF can has an open winding or something. I can twiddle any slug I want, all it does is sound like a radio not tuned to any station. Gotta dig back into that thing at some point.

Might want to check that it don't have silver mica disease.

dtvmcdonald
07-28-2016, 05:56 PM
Unfortunately this problem sounds like a bad main IF alignment, or else a fault
in an IF can, after fixing of which an alignment is needed.

Despite what some people say, every single postwar set I have has been
seriously out of alignment, even if it "worked OK". The picture quality and picture-sound tuning spot coincidence has been improved by either a tweek or
full alignment. If you tweek, only tweek one adjustment and return to original if
it does not completely fix the problem ... hoping that one big tweek and
one little one will 100% fix it is well on the road to Hell.

My TRK-12 was spot, perfect, on. If I could feed its video into a CT-100 it would produce a perfect color picture. The TT5, pretty much per spec, but a one-coil
tweek made it look better.

Phil Nelson
07-28-2016, 08:46 PM
the audio is not at the same tuning position as the clear picture signal. I suspect an audio alignment may be necessary.Is there any fine-tuning spot where the audio is loud and clear? (That would rule out silver mica disease and show that your audio section is basically OK.) On some sets where the audio has separately drifted away from the video, you can "walk" the audio alignment back into step with the video by carefully tweaking the audio adjusters while watching and listening. This is lower-risk than attempting a full-dress alignment of video and audio IFs.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
07-28-2016, 08:49 PM
Is there any fine-tuning spot where the audio is loud and clear? (That would rule out silver mica disease and show that your audio section is basically OK.) On some sets where the audio has separately drifted away from the video, you can "walk" the audio alignment back into step with the video by carefully tweaking the audio adjusters while watching and listening. This is lower-risk than attempting a full-dress alignment of video and audio IFs.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

No matter where i fine tune the audio its always got that horrible overmodulating hum (not filter cap hum). It gets louder as I turn the knob to the right.

Electronic M
07-28-2016, 11:53 PM
http://www.videokarma.org/attachment.php?attachmentid=191973&d=1469657021

"Ahhhhh! Patrick! The screen looks like a fishbowl and I see wavy lines everywhere!"

Now that the picture loads....

I think this NEEDS to become a VK web meme! :D

SwizzyMan
08-24-2016, 05:13 PM
Just put in an order for the filter caps. Hope to get started this weekend! :D

bigaudioal
08-25-2016, 11:38 AM
5 is the only one with weak HV, you won't have any trouble getting a full 24/25 KV out of this set.

When working with my CTC-5 last week I noticed that all the service literature I have says between 19.5 - 22.5kV at the CRT anode. My CTC-5 is putting out exactly 20kV.

Why do I constantly see folks complaining about the CTC-5 not putting out 25kV when all the original service literature says lower than 25kV for this set is normal?

SAMS for early CTC-5 says 22.5kV
RCA Original Service Manual says 19.5kV
RCA Original Setup Manual says 20kV
SAMS for late CTC-5 says 22kV

See attached snip-its from some of that literature.

Just wondering as I have limited experience with vintage color sets.

Thanks.

miniman82
08-25-2016, 04:16 PM
When working with my CTC-5 last week I noticed that all the service literature I have says between 19.5 - 22.5kV at the CRT anode. My CTC-5 is putting out exactly 20kV.


The problem is not the literature for the chassis, it's the specification itself. Not only did they choose an anode supply for the 5 chassis which only provides around 20kv to the CRT, they also for some unknown reason decided to not make up for that lack of voltage by having ample current reserves. To understand why this is a detriment, see note 3 of this PDF on the 21AXP22:

https://frank.pocnet.net/sheets/137/2/21AXP22.pdf )

I say lack of voltage because the 5 is the only one that low, all other chassis (especially the earlier ones) made a full 25kv and had more than enough current in the anode supply to make a full and bright picture without trying very hard. Add this to the fact that the data sheet on the CRT even tells the engineers that less anode voltage equals less brightness, and it will always be a mystery to me why RCA chose in this one particular chassis to do what they did. I don't care to speculate why it happened, it's an issue and makes the 5 a real dog in the brightness department compared to other sets.

Electronic M
08-25-2016, 04:47 PM
The problem is not the literature for the chassis, it's the specification itself. Not only did they choose an anode supply for the 5 chassis which only provides around 20kv to the CRT, they also for some unknown reason decided to not make up for that lack of voltage by having ample current reserves. To understand why this is a detriment, see note 3 of this PDF on the 21AXP22:

https://frank.pocnet.net/sheets/137/2/21AXP22.pdf )

I say lack of voltage because the 5 is the only one that low, all other chassis (especially the earlier ones) made a full 25kv and had more than enough current in the anode supply to make a full and bright picture without trying very hard. Add this to the fact that the data sheet on the CRT even tells the engineers that less anode voltage equals less brightness, and it will always be a mystery to me why RCA chose in this one particular chassis to do what they did. I don't care to speculate why it happened, it's an issue and makes the 5 a real dog in the brightness department compared to other sets.

Add to that the fact that some chassis versions have a bass-ackwards brightness/contrast control circuit that has lots of interaction between controls, and some users were literally sending working sets to the repair shop because they could not manage to set the controls for a good watchable picture.

The 5s are the BOTB RCA color chassis in my book. If I had a nice 5 with a good 21AXP as well as my beat up 4 with a bad AXP I'd consider the 4 more worthy of the rare AXP.

bigaudioal
08-25-2016, 04:49 PM
The problem is not the literature for the chassis, it's the specification itself. Not only did they choose an anode supply for the 5 chassis which only provides around 20kv to the CRT, they also for some unknown reason decided to not make up for that lack of voltage by having ample current reserves. To understand why this is a detriment, see note 3 of this PDF on the 21AXP22:

https://frank.pocnet.net/sheets/137/2/21AXP22.pdf )

I say lack of voltage because the 5 is the only one that low, all other chassis (especially the earlier ones) made a full 25kv and had more than enough current in the anode supply to make a full and bright picture without trying very hard. Add this to the fact that the data sheet on the CRT even tells the engineers that less anode voltage equals less brightness, and it will always be a mystery to me why RCA chose in this one particular chassis to do what they did. I don't care to speculate why it happened, it's an issue and makes the 5 a real dog in the brightness department compared to other sets.

Ah, I see. So it was the design of the set which produces the lower HV, thus being the least adequate to run the AXP. So the set literature is accurate and the 20kV is "normal" for a CTC-5. But that is barely enough to produce a decent picture compared to other sets of the same time period which produced around 25kV.

Very strange they did that considering the specs and notes on the CRT they were using.

bigaudioal
08-25-2016, 04:51 PM
Add to that the fact that some chassis versions have a bass-ackwards brightness/contrast control circuit that has lots of interaction between controls, and some users were literally sending working sets to the repair shop because they could not manage to set the controls for a good watchable picture.

The 5s are the BOTB RCA color chassis in my book. If I had a nice 5 with a good 21AXP as well as my beat up 4 with a bad AXP I'd consider the 4 more worthy of the rare AXP.

I have noticed blooming and focus issues while adjusting both the brightness and contrast controls.

SwizzyMan
08-25-2016, 05:11 PM
Doesn't this set need to be registered in the ETF's database of surviving CTC-4's?

miniman82
08-25-2016, 09:57 PM
Very strange they did that considering the specs and notes on the CRT they were using.

That's why it's the runt of the litter, so to speak. For the same reason I, like Tom said, would cannibalize a 5 to get a CRT for a more deserving set. Done it many times. About the only ones that don't fall into that category for me are the more rare Deluxe doored models like yours, my Wingate and maybe a few others. But apart from that, they fall into the category of donors.

miniman82
08-25-2016, 09:57 PM
Here's a thread talking about the circuit mods, BTW.

http://www.videokarma.org/showthread.php?t=256638&page=2

bigaudioal
08-25-2016, 11:49 PM
Thanks very much!!!

SwizzyMan
08-27-2016, 09:40 PM
Pulled the chassis tonight. Multiple repairs have been done. You can tell it was owned by a repairman. I have already started recapping the filter caps. More to come later.

SwizzyMan
08-28-2016, 09:56 PM
It's amazing what a bit of tarni-shield and elbow grease can do! :D

old_tv_nut
08-29-2016, 08:11 PM
That's why it's the runt of the litter, so to speak. For the same reason I, like Tom said, would cannibalize a 5 to get a CRT for a more deserving set. Done it many times. About the only ones that don't fall into that category for me are the more rare Deluxe doored models like yours, my Wingate and maybe a few others. But apart from that, they fall into the category of donors.

Reading the nth explanation of the 5, got me thinking:

1) Did the DeLuxe, with its better color, video, and sound circuits, have the same low HV as the Super? If so, that's a shame.

2) If you consider the 5 as a donor anyway, how about the possibility of rebuilding the HV section based on a better design. Maybe the main replacement needed would be only the fly, with the same yoke? Or maybe you'd need both? If this makes sense, I'd be tempted to try it on my 5, which makes me cry because it's got a good CRT being shown to such poor advantage.

miniman82
08-30-2016, 05:17 PM
Wayne,


This is a problem with all 5 chassis, including the Deluxe ones unfortunately. The problem is the flyback, it's got a lot more primary resistance than other models. This means there's a practical limit to how much current the HOT is able to sink, which in turn limits how much HV can be made in the secondary (lower current primary pulses means lower amplitude flyback rectification in turn). I'm not sure why this was done, but it appears to be in the design and intentional. Perhaps the engineers wanted it to be 'safer' or something, we'll likely never know.

I have a few different flybacks I can try in my Wingate (CTC-4, CTC-28, CTC-15), but the problem is not getting more HV or a yoke inductance match from the swap- there are ways around both those problems. It's getting all the ancillary circuits to play well with the new transformer that's a big question. None of the tertiary windings that provide pulses to circuits like burst gating or AGC appear to be common across chassis to me, which makes the job of adapting them much harder. Some flybacks had positive going pulses, some negative. Some had very high amplitude AGC, some not. What I see is probably a matching/inverting network and possibly some slight phase shifting to make the new fly work. It won't be a plug in deal unfortunately.


BUT- the payoff would be a very nice chassis indeed. The deluxe sets had good circuits in them for color processing, they just had a wimpy horizontal output transformer. I'm going to give it a shot at some point, and I'm also going to try primary side pulse style HV regulation. It'll be like reengineering a complete section of the chassis.

SwizzyMan
09-01-2016, 05:23 PM
Still have 2 more filter caps to replace, but I thought I'd do a power up to see where I'm at. Current draw is about 2.5A and only putting out about 3 KV. I don't believe the HV readings since the yoke is not plugged in and all I'm using is a piece of wire to short the yoke connection so the HV will actually come up. Found a 80 uf in place of a 40 uf in one of the filter caps and most of the hacked in filter cap replacements had shot their crystallized goo out the side already. Things are going well! :thmbsp:

Electronic M
09-01-2016, 06:30 PM
Personally I'd pull the H output tube, till the recap is done and the osc. has been dialed in with a scope. Don't want to risk your flyback. On my 4 I did it that way, and when I was ready to install the tube I had it set up to dip the cathode current using the linearity/efficiency slug as soon as I had HV....I pretty much confirmed I had decent sweep and HV then immediately dipped the current. If something is wrong and the fly is being fed too much current, you don't want to run it that way long....We refer to flys for early sets like this as unobtainium for a reason!

SwizzyMan
09-01-2016, 06:46 PM
Personally I'd pull the H output tube, till the recap is done and the osc. has been dialed in with a scope. Don't want to risk your flyback. On my 4 I did it that way, and when I was ready to install the tube I had it set up to dip the cathode current using the linearity/efficiency slug as soon as I had HV....I pretty much confirmed I had decent sweep and HV then immediately dipped the current. If something is wrong and the fly is being fed too much current, you don't want to run it that way long....We refer to flys for early sets like this as unobtainium for a reason!

Amen to that! Only had it running 2 minutes. Still a bad idea on my part. I already heard john h's horror story with the flyback in his 4.

SwizzyMan
09-01-2016, 08:59 PM
Replaced the seleniums with 1n4007s. Did a 30 second power up. Once the relay to turn on the HV switched on I blew the 4.5 A fuse. I double checked the polarity of the diodes and they are correct. Im thinking I may need to add a dropping resistor.

miniman82
09-03-2016, 05:18 AM
If it's a B+ relay, you need to short across it to form the capacitors initially. The inrush current is what made the fuse pop, if you find it a repeated problem add an NTC to the line.

SwizzyMan
09-05-2016, 11:50 AM
Or I might just delete it completely. Sure soft start is good, but it's not going to be used that much to the point when soft start may be needed.

SwizzyMan
09-05-2016, 08:39 PM
so I shorted out the relay to simulate having no B+ relay at all. Also I switched the polarity of the silicon diodes to the band end facing towards positive. I powered it up and no action whatsoever. No pilot light no tube filaments. But the HOT damper and I think the shunt regulator tube filaments are glowing. I think the diode polarity is wrong, or i killed the filament winding on the power transformer.

ChrisW6ATV
09-05-2016, 09:33 PM
There are two "fuses" in the filament circuits that are actually pieces of fine wire (30 gauge maybe?). Check those; one or both may have blown.

SwizzyMan
09-06-2016, 05:06 PM
Y leg of the filament supply had a blown wire fuse. Temporarily twisted it together for a power up. Filaments are back and HV is back and strong. Filter cap recap finished. Might be ready to shove the chassis back in and see what the CRT has to say. Still tests wacky on 6.3 but springs to life at 7v.

Electronic M
09-06-2016, 10:46 PM
Well if the tube is dim and won't focus well at 6.3V you could always try boosting to 7V later.

SwizzyMan
09-10-2016, 01:19 PM
Here are some shots after the filter caps were replaced. Produces a crystal clear B&W picture, but color isnt looking good. Have to pretty much turn the color knob all the way up to get any color, but the hue is all wrong which I contribute to purity issues since the set is in a different position than the one it was in the last time it was powered up. Still have that pesky interference that comes in when the color is turned on. And it looks like the element on the electron gun is a bit discolored so that may explain why this tube is a bit weak at 6v. Everything is going well so far. Now I need to do a full recap.

SwizzyMan
09-11-2016, 12:46 PM
Ive noticed that this crystal in the color circuit rattles when I tap on it. This doesnt seem right.... Might need to buy a replacement. This might contribute to the incorrect colors.

old_tv_nut
09-11-2016, 01:23 PM
If the oscillator doesn't quit when you tap on the crystal, it's still OK. Just stop tapping on it in case you might break it.

SwizzyMan
09-11-2016, 07:35 PM
Well Hopefully the chroma issues will clear up once I do a recap. I really hope I dont need to do an alignment. Put the chassis back on the bench and I'm going to order a full set of caps soon. Hope to get this working before the Christmas holiday season.

SwizzyMan
09-18-2016, 06:15 PM
Replaced about 15 of the paper caps so far. Probably going to have to fix my filter cap arrangement, kinda sloppy. The recap of the paper caps is coming along nicely. Most of them seem to be original caps. Bet I could sell these two bumblebombs for a pretty penny to the audiofools.:naughty: More to come later.

SwizzyMan
09-20-2016, 04:22 PM
I have noticed something strange. I was trying to figure out if my chassis is a early or late production chassis. Reading Bob G's article on CTC-4 chassis variants determined that my chassis was an early production chassis. One thing I have noticed is that the RCA service manuals and schematics calls for a 3.58 MC oscillator crystal, but the sams calls for a 3.579545 which is extremely close to 3.58 Mhz. This crystal seems to be a factory original part of the set, but I am confused as to why there isnt a 3.58. Maybe RCA ran out of 3.58's and used 3.579545 to substitute. I must also mention that the crystal in the set rattles when I lightly tap on it.

Electronic M
09-20-2016, 04:36 PM
The difference is because of a mathematical practice called Rounding....In many engineering disciplines (including electrical engineering) rounding to 3 digits is common practice.

One drawing just has an unnecessary number of sig figs.

old_coot88
09-20-2016, 04:39 PM
3.58 is simply the rounded-off figure. "Three fifty-eight crystal" or 'color crystal' is all the same thing.

old_tv_nut
09-20-2016, 06:33 PM
If the oscillator uses the crystal alone as a series resonant element, the crystal is tuned to be series resonant (a short circuit) at 3579545 Hz. However, nearly all chroma oscillators use a crystal in a "parallel resonant" mode. I put "parallel resonant" in quotes because the crystal is not tuned to be parallel resonant in itself, but to be inductive, so it can be either series resonant or parallel resonant when combined with a small amount of capacitance (consisting of both strays and discrete separate parts). In this mode, the crystal acts as a very large inductor resonating with a small capacitance, and the combination is resonant at 3579545 Hz. The crystal series resonance in itself is then a few hundred Hz different from the correct frequency. Common values for the total tuning capacitance would be in the range of 20-30 picofarads. The value of capacitance for which the crystal is tuned is specified in a manufacturer's part drawing, but not in service literature. Generally, crystals made for different values of capacitance can be substituted because in most cases the oscillator center frequency can still be tuned to the correct value; however, the pull-in range and hence the temperature drift will be different than intended.

SwizzyMan
09-20-2016, 07:32 PM
Might have to replace the crystal. It rattles when barely tapped. And as I was recapping I accidentally hit it with my pliers.

Phil Nelson
09-20-2016, 09:04 PM
I would suspend judgement on the 3.58-Mhz crystal until you finish recapping and try the TV again. If the crystal is bad, the telltale signs should be pretty obvious, as I observed when working (and working and working) on my poor old CTC-4. It will be easier to diagnose that after you eliminate bad caps from the color circuits.

If you do eventually find that your crystal is bad, I can send you a spare from my stash.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
09-20-2016, 09:38 PM
Good Idea Phil. Better to narrow it down first. It was working last time I powered it up since the color oscillator was in fact running at the correct frequency. I really appreciate your offer to send me a crystal if the need may arise. Thanks!

SwizzyMan
09-27-2016, 09:08 PM
Only have about 7 more paper caps to replace. Some values Im going to have to order. Going to do a power up later this week. Found one of those El-shitco caps that the ceramic case had cracked and the inside was almost hollow... wow.

SwizzyMan
09-30-2016, 05:38 PM
Fixed the previous issue. I have a few more paper caps to replace which are values I didn't have on hand. Did a power to see where I'm at. Still pretty much the same when the old caps were still here. Didn't expect recapping to do much since that's not how it usually works.

SwizzyMan
10-04-2016, 04:48 PM
Here is what I got. As you can see I have a nice black and white picture. But the color is a different story. There seems to be an absence of yellow and any purple colors. Rotating the Hue didnt do much and this was the best I could get it. I also have to turn up the color control about 3/4 of the way up to really get any color. And you can see i have that slow horizontal bending that almost looks like bad filters (all were replaced)when straight lines show up on the screen. I almost suspect that the crystal oscillator is actually bad.

Electronic M
10-04-2016, 05:18 PM
Have you checked the tubes recently for Heater-Cathode/Heater-anything shorts...That could be introducing your hum bar.

On my set I had to adjust one of the transformers in the color demodulator....The one that controls the phase angles that the 2 demods operate on....It has an above chassis and a below chassis adjustment on it's can...You have to adjust both at once with color bars on screen, and you have to use 2 plastic flat edge alignment tools (metal screw drivers will make your adjustments shift as soon as you remove the drivers from the can)....I had to make my 'alignment tools' out of ruined mechanical pencils. I wish I could tell you which can it is, but it has been ~4 years since I did that work.
http://videokarma.org/showthread.php?t=252909&highlight=Barberized+Seville&page=4

old_tv_nut
10-04-2016, 05:24 PM
You appear to have horizontal sync problems. Since this could affect color burst gating, you should probably fix the sync first. Those wigglies could come from poor sync separation, a problem with the horizontal AFC, or even a bad signal level due to AGC problems or wrong AGC setting - suggest you hunt down the horizontal trouble, and check the burst gating before tackling color. The color oscillator is probably OK, since you have stable (but wrong) colors.

To clarify: I would try the simplest things first - try adjusting the AGC to see if it makes any improvement.

Phil Nelson
10-04-2016, 06:53 PM
Amen to Wayne's advice to look at simpler causes before you mess with color circuits/adjustments. To quote various old manuals, make sure you have a perfect (well, darned good and stable) black and white picture before you tackle color stuff.

If your 3.58-Mhz oscillator wasn't working, you'd more likely have rolling "rainbow" bands of color, not stable bars, as I learned in struggling with my sad old CTC-4.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

http://antiqueradio.org/art/RCACTC-4T115OutputsPhased3.jpg

http://antiqueradio.org/art/RCACTC-4HoveringColorBars.jpg

SwizzyMan
10-04-2016, 07:33 PM
Now that I think about it. I had this problem with my pensbury. A 68k resistor went off value and caused the horizontal sway. Hopefully its just an AGC adjustment on this set.

SwizzyMan
11-16-2016, 06:29 PM
Finished recapping (finally). I have to say some spots were very hard to work at, the convergence module being the most difficult. Overall recapping this set was relatively stressful to the fact I was working around fragile coils and try not to drip any solder on anything. I also made sure to check all my connections with my Ohmeter. I decided to give it the shrink wrap treatment since this set is a hard to find set and neatness is a must. I have yet to fire it up and quite frankly im a bit scared to do so since Im worried I might have accidentally broken a coil or a coil in the convergence module, while I don't recall messing up too bad anywhere (with the exception of 2 or 3 solder dropping mishaps) I'm still scared out of my mind about powering it up since this set is relatively rare. I hope the power up goes well! :sigh:

SwizzyMan
11-18-2016, 08:35 PM
Did a power up and all went smoothly thank God! Still have the same problem, superior black and white picture but piss poor color. Still got that pesky interference. Adjusting the AGC control helped a little with the interference. It is also becoming increasing evident that the red gun is pretty weak, and its impossible to do a color temperature set up according to the service manual. What really puzzles me is the absence of all other colors pretty much except for blue and red on the color bars. I adjusting the hue coil (T125) for about half a turn and realized that wasnt it so I returned it back to its original position. adjusting the hue control really doesnt make much difference. The red and blue bars stay there until about a full turn ccw when they shift to maybe a purple color. Also i must not I have to turn the color control to pretty much the max color setting to really get any sort of a chroma signal. This further backs up the statement that replacing capacitors on antique tv or radio doesnt always magically fix everything. Any ideas on what is wrong here and any possible adjustments i can do?

Electronic M
11-18-2016, 10:53 PM
One thing you should do is degauss it and perform a purity adjustment.

A note the coil that changes the hue and relative demodulation of the different bars has 2 slugs one bottom and one top (should be flat edge blade adjustments)...On that coil you want to adjust both simultaneously with plastic adjustment tools (metal ones will skew the adjustment once removed).

old_tv_nut
11-18-2016, 11:00 PM
You say "superior black and white picture", but I don't see the correct luma in the color bars. Do you actually get nice gray level steps on the color bars when you turn the color down?

SwizzyMan
11-19-2016, 07:17 AM
Yes, I just need to adjust the brightness.

SwizzyMan
11-19-2016, 09:59 PM
One thing you should do is degauss it and perform a purity adjustment.

A note the coil that changes the hue and relative demodulation of the different bars has 2 slugs one bottom and one top (should be flat edge blade adjustments)...On that coil you want to adjust both simultaneously with plastic adjustment tools (metal ones will skew the adjustment once removed).

Ill have to try both of those suggestions. Anyone else have any ideas? I almost feel the weak red gun may partly be at play here.

Phil Nelson
11-20-2016, 03:52 AM
Instead of trying adjustments piecemeal, I would recommend working through the setup procedures described in the service manual. This article has a link to the 91-page RCA manual:

http://antiqueradio.org/RCACTC-4ColorTelevision.htm

Those procedures include purity, convergence, tracking, color AFC, etc. Follow the order given in the manual. First, as noted, make sure you have a good "black and white" picture. Then comes purity, and so on.

There's a reason why the factory doc describes this stuff in detail and in a particular order. The complete setup on an early color set is not something that the average consumer could "eyeball" by whipping out a screwdriver and turning random adjusters for a minute or two.

If you're patient and your TV is in good shape, the CTC-4 will reward you with a very nice color image.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
11-20-2016, 07:36 AM
Instead of trying adjustments piecemeal, I would recommend working through the setup procedures described in the service manual. This article has a link to the 91-page RCA manual:

http://antiqueradio.org/RCACTC-4ColorTelevision.htm

Those procedures include purity, convergence, tracking, color AFC, etc. Follow the order given in the manual. First, as noted, make sure you have a good "black and white" picture. Then comes purity, and so on.

There's a reason why the factory doc describes this stuff in detail and in a particular order. The complete setup on an early color set is not something that the average consumer could "eyeball" by whipping out a screwdriver and turning random adjusters for a minute or two.

If you're patient and your TV is in good shape, the CTC-4 will reward you with a very nice color image.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I'll go through a complete set up procedure today and report back with my findings. I probably could be a bit more patient with this set but I'm a bit behind schedule on my goal to have a decent picture by Christmas.

SwizzyMan
11-20-2016, 11:42 AM
So I tried going through the setup as indicated by the manual and I couldnt even get past screen temp without an issue. I followed the instructions in the manual. I couldnt get the "barely visible red screen" and I think I know why. I went to measure the bias on the Red grid and cathode as i adjusted the brightness and the voltage was way too low. Im talking almost 200v below the intended 70v. I did have all controls adjusted correctly while checking the bias and adjusting the brightness for a dim red raster. I suspect a resistor downstream of the red screen control or downstream of the cathode and grid has drifted way too low or has even shorted. I guess ill have to do some investigation. This all seems odd since I at one point did have red in my color picture and things looked pretty watchable, but now its kinda taking a turn for the worse. I have one picture attached of what it used to look like before I really recapped any paper caps.

SwizzyMan
11-23-2016, 07:43 PM
Any advice anyone? I think I may have a weak tube at this point...

Hagstar
11-23-2016, 07:53 PM
With my CTC4 I ended up getting all NOS tubes which I've never done for any radio or TV. BUT these early color sets run them too hard. I can't get stable color with any of my used tubes in the chromiance section even though they test fine on the Hickok.

SwizzyMan
11-23-2016, 07:59 PM
With my CTC4 I ended up getting all NOS tubes which I've never done for any radio or TV. BUT these early color sets run them too hard. I can't get stable color with any of my used tubes in the chromiance section even though they test fine on the Hickok.
Good idea John. I did suspect the 12BH7 r-y demod. Tested fine. I'll pick a whole new set except for h-out and he circuit tubes.

SwizzyMan
12-04-2016, 07:35 PM
Could this be a weak red gun? Id think if the red was weak of course shades of certain colors that use red would be way off. I just need to know if I should start hunting for another tube.

miniman82
12-07-2016, 04:41 PM
hook up a CRT tester and find out

benman94
12-07-2016, 05:10 PM
That set has so many major problems that the LEAST of your worries should be the condition of the CRT. Replacing the CRT is not going to be some magical cure for your issues. Put it on a tester if you like, but even a good tube would produce a terrible picture when driven by that chassis.

SwizzyMan
12-07-2016, 07:19 PM
I didn't believe it would be a magical cure, but the red gun tests really weird and I thought that it might be a pretty weak gun and in result colors that use red would be either not present or incorrectly colored. This set is a real pain so far. But I'm going to just start with a fresh brand new set of tubes and go from there. Something tells me I will probably be doing some alignments :sigh: . The red gun on the CRT tests good at first but then 1 second later the needle swings pretty erratically but the swinging stay within the ? And good range. Both other guns do this but not nearly as much. And I've found also that the red screen control does almost nothing too, I'll have to check it.

Electronic M
12-07-2016, 07:35 PM
Does your CRT tester's instructions mention how a gassy tube should test....It might be getting gassy.

SwizzyMan
12-07-2016, 07:46 PM
Does your CRT tester's instructions mention how a gassy tube should test....It might be getting gassy.

No it doesnt. It did this when I got it about 4 months ago so if it's getting gassy it's extremely slow and it isn't gassy enough to kill the picture. I don't think it's gassy.

benman94
12-08-2016, 07:12 AM
The fact that you aren't seeing red doesn't automatically point to the red gun of the CRT. You could (and almost assuredly do) have a matrix or demod issue. My CT-100 had problems in the red adder that completely killed any red on the screen; the 15GP22s strongest gun was actually the red gun however.
If the tube was going gassy, I strongly suspect you'd have at least major focusing issues, etc.
Get the chassis working first, then worry about the CRT. Even if the CRT is garbage, I'd finish the restoration and wait for a clunker CTC-5 with a good 21AXP22 to surface. There's little point in having an operational CTC-4 without a good 21AXP22, and you'd be throwing good money after bad by putting another 21FBP22 or 21FJP22 in it.

SwizzyMan
12-09-2016, 08:48 PM
Started to replace some tubes. I also tested the tubes I was replacing and noticed that the 12BH7 R-Y Demod tube has a cathode short. This could explain the absence of red. This short didnt show up on the hickok 600a, but it did show up on the WT-100a. The WT-100 has an extremely sensitive shorts test so I guess it was able to pick it up.

SwizzyMan
01-31-2017, 09:00 PM
I've been thinking about stealing the 21ax out of the 5 and putting it in the 4. Does anyone have a glass retrofit kit for the 5? I'm not sure it's a good idea really, but I am looking for authenticity.

old_tv_nut
01-31-2017, 10:36 PM
I hope you can find a real retrofit kit, but they are scarce. I never found one. I used some CTC-7 pieces plus miscellaneous jury-rigged hardware to put a glass tube in my 5 until I could get a 21AX. Regarding authenticity, there is no visible difference from the front, and you can do it without destroying any part of the 5 (just save a few parts like the plastic funnel and edge magnets in a box), so if/when you get another 21AX, you can always reverse it.

Steve D.
02-01-2017, 04:48 PM
I've been thinking about stealing the 21ax out of the 5 and putting it in the 4. Does anyone have a glass retrofit kit for the 5? I'm not sure it's a good idea really, but I am looking for authenticity.

My CTC-5 Wingate has the metal to glass RCA Victor retrofit kit to accommodate the 21FBP22 tube that was in it at the time I purchased the set many years ago.
I have never seen another factory kit.

-Steve D.

DaveWM
02-01-2017, 04:59 PM
that kinda looks like what holds the CRT in my RCA roundie Test Jig.

Electronic M
02-01-2017, 05:30 PM
Don't know if it would help, but I do have a spare CRT mount assembly out of something like a CTC-15 that I'd sell.

SwizzyMan
02-09-2017, 07:24 PM
Sounds like too risky of an operation. Let's just get it going first i guess.

SwizzyMan
02-18-2017, 05:02 PM
I replaced a shorted 12BH7 (R-Y G-Y Demod) and a shorted 6AG7 (Demod driver) tube hoping I would see at the least a bit of improvement. Well there was none whatsoever, if anything the picture quality has gotten worse by just sitting for a mere month. I still have no red which pisses me off since I really thought the shorted R-Y demodulator tube might have given me a hint of red when replaced. At one point I had red. Once I did a recap, I lost it which doesnt make any sense to me. Also I still need to figure out what all the interference associated with the color being present in the picture is all about. While I had the chassis on the bench testing voltages and checking wave forms, a resistor started smoking. It was a 10K 2watt resistor feeding a 285v supply off of the demodulator coil, its value has now risen out of tolerance so I will replace it regardless. Not sure if this may be an issue with the total absence of red. There is also a thick line on the side of the crt when the set it on, doesnt look like a drive line to me. Ive got my work cut out for me and I still have a lot to learn about these sets even though Ive restored two other roundies. Anyone here have any ideas on where i would even begin to look?

DaveWM
02-18-2017, 07:00 PM
if it had red at some point before doing a recap, then you should check your work.

also, checking pin voltages is 1st (think you did this early on and there were issues with voltages at CRT pins)

if the Purity is way out, then getting good red will be an issue as well.

How does the CRT check for emissions and cut off?

old_coot88
02-18-2017, 07:03 PM
It looks like the 3.58 oscillator isn't running.

DaveWM
02-18-2017, 07:22 PM
good point about the osc, I am used to seeing the rainbows in the pic, but that is when its not synced up, could be not running at all. Get the scope and see if you can get a wave form from the color osc.

SwizzyMan
02-18-2017, 07:51 PM
I am pretty sure the xtal is bad then. I mentioned earlier in this thread that it rattled when tapped on. Ill check for waveforms , but ill probably need a new crystal. Does anyone have one? Emissions are weird and somewhat weak at 6.3 but spring to life at about 7.5 volts. But ive known not to trust my crt tester sometimes. It tests good enough at 6.3 to at least produce some red.

SwizzyMan
02-19-2017, 11:12 AM
I think Ive confirmed that the 3.58 oscillator is not running. I checked for waveforms on both sides of the crystal and I got nothing at all. Keep in mind I took this measurement with color control fully up, but not connected to the CRT so no HV or anything. I think I have a bad crystal.

Hagstar
02-19-2017, 12:25 PM
Rattle in a crystal sure is a bad sign. These are easily obtainable (eBay etc.) but beware most are for transistorized TVs, a larger earlier one is what you want. Usually these are in the HC33 size case.

SwizzyMan
02-19-2017, 03:22 PM
It actually turns out the smoking resistor is a 5k 10w coming off the color take off coil and feeding another 285v supply. I dont see any brown spots where burning has occurred on the resistor itself and I know a 10 watt dissipates a lot of heat. So it may just be dust on top of it burning off. But i recall never seeing any smoke until now coming from it. I checked tubes associated with it and none were shorted. I noticed that the resistor has a connection to G1 of the AGC amp tube. I had been adjusting the AGC in hope it may have given me a better picture, not sure if its set too high, but I dont think adjusting the AGC would cause this.

Phil Nelson
02-19-2017, 07:29 PM
I think Ive confirmed that the 3.58 oscillator is not running. I checked for waveforms on both sides of the crystal and I got nothing at all. Keep in mind I took this measurement with color control fully up, but not connected to the CRT so no HV or anything. I think I have a bad crystal.In my CTC-4 article (http://antiqueradio.org/RCACTC-4ColorTelevision.htm ) you can read about various tests I performed around the color oscillator. It includes a procedure for bench testing your crystal, suggested by dtvmcdonald.

If you confirm that your crystal is a goner, shoot me a PM. I have a couple of spares lying around and I could donate one to the cause.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
02-19-2017, 08:46 PM
In my CTC-4 article (http://antiqueradio.org/RCACTC-4ColorTelevision.htm ) you can read about various tests I performed around the color oscillator. It includes a procedure for bench testing your crystal, suggested by dtvmcdonald.

If you confirm that your crystal is a goner, shoot me a PM. I have a couple of spares lying around and I could donate one to the cause.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I'll Have to take you up on that offer! I tested for both a waveform and voltages on pin 6 of the 6AZ8 and I got absolutely nothing for both....Crystal is dead. I'll send you a PM.

Electronic M
02-19-2017, 09:39 PM
It actually turns out the smoking resistor is a 5k 10w coming off the color take off coil and feeding another 285v supply. I dont see any brown spots where burning has occurred on the resistor itself and I know a 10 watt dissipates a lot of heat. So it may just be dust on top of it burning off. But i recall never seeing any smoke until now coming from it. I checked tubes associated with it and none were shorted. I noticed that the resistor has a connection to G1 of the AGC amp tube. I had been adjusting the AGC in hope it may have given me a better picture, not sure if its set too high, but I dont think adjusting the AGC would cause this.

That resistor is a red flag odds are there is a short or a mis-biased tube drawing too much current through it. Do voltage checks in the area around that resistor and on any tubes it feeds.

SwizzyMan
02-20-2017, 12:13 PM
It has to be an improperly biased tube causing the resistor to overheat. I checked almost everything downstream of it and found no shorted components. Will check voltages later.

SwizzyMan
02-20-2017, 06:35 PM
Was going to check voltages so I reconnected both resistors. After pulling the noise inverter 6u8 since it was connected to the resistor (thinking this may be the mis-biased tube.) to check for smoke, I got none. I put it back in the socket and still no smoke. The 5k resistor is no longer smoking and burning up. It is still warm to the touch but not burning hot. I now need to replace the 3.58 crystal. Phil Nelson was kind enough to donate a crystal to the cause so Im waiting on that getting here.

DaveWM
02-20-2017, 07:42 PM
shorted tubes can smoke resistors, and shorts can be intermittent.

andy
02-20-2017, 09:32 PM
The underside of the CTC 4 is such a rats nest that it's easy for wires to short together. I had a similar issue on the CTC4 I'm restoring.

Hagstar
02-20-2017, 09:35 PM
I wasted a lot of time on my CTC-4 thinking Hickok tested meant something. Indeed failure to work as a chroma amp or intermittent shorts weren't always detected. Tubes are cheap enough, and those 6U8s and AZs are considered expendable under such heavy use. I just order NOS (usually Sylvania or GE) for all critical tubes for any color set so old and keep the old ones for emergency/if they work spares.

SwizzyMan
02-21-2017, 06:36 PM
I'll look around for any shorted wires, but my next order of business is to figure out how to get rid of the interference when the chroma signal comes in. It makes the picture unwatchable. I also have a bit of artifacts on the black and white signal now. I may just shotgun replace all resistors on the video board for good measure, but the chroma signal interference might be a different story.

SwizzyMan
03-21-2017, 07:32 PM
Got a new oscillator crystal courtesy of Phil Nelson (Thanks a bunch). I got it awhile ago in fact. I just haven't had time to get back to the set until this weekend. Hopefully replacing the bad crystal will clear up some problems. It's been almost a year working on this set and i've still got a ways to go. :thumbsdn:

Tubejunke
03-23-2017, 02:32 AM
Perhaps there is some arcing that is causing the interference?


My thoughts exactly as I looked at those screen shots. Iím by no means a color TV expert, but I do have a Zenith roundie that had the slightest arching in the HV cage. It was hardly audible, but that was exactly what the picture looked like. Turned out that the HV rectifier socket was fried. Replaced that and no problems. In addition, I think that set needs degaussing. Most of us arenít lucky enough to have a real servicemanís degaussing ring, so I just use my Weller soldering gun in the same manner that you would use the ring.

Electronic M
03-23-2017, 08:08 AM
My thoughts exactly as I looked at those screen shots. Iím by no means a color TV expert, but I do have a Zenith roundie that had the slightest arching in the HV cage. It was hardly audible, but that was exactly what the picture looked like. Turned out that the HV rectifier socket was fried. Replaced that and no problems. In addition, I think that set needs degaussing. Most of us arenít lucky enough to have a real servicemanís degaussing ring, so I just use my Weller soldering gun in the same manner that you would use the ring.

I've got a real service degaussing coil and I've made spares....Allz you have to do to make one is find a decent sized 20" or bigger BPC set at the curb, steal it's degaussing coil, loop that 3 times around so it becomes a smaller coil ~12-14" in diameter, wrap it in electrical tape so it holds that form, and attach a cord.
...It will get hotter faster than a servicing coil, but one can get about a minute run time (plenty for most sets) out of it before it needs a cool. I made a thread on the process a while back.

jr_tech
03-23-2017, 11:09 AM
I think that this handy tip should have been made a sticky:

http://www.videokarma.org/showthread.php?t=264048&highlight=degauss

jt

Electronic M
03-23-2017, 12:24 PM
I think that this handy tip should have been made a sticky:

http://www.videokarma.org/showthread.php?t=264048&highlight=degauss

jt

I've made it into one.:thmbsp:

dieseljeep
03-23-2017, 09:59 PM
I've made it into one.:thmbsp:

I picked up a Radio Shack bulk tape eraser, that works great! It's a black plastic unit, that looks like a travel iron. It's a real powerful item, that can be used to demagnitize, just about any kind of magnetic media. It also works well as a deguasser, even though, I still have the first RCA DG coil, I bought over 50 years ago. :scratch2:

kvflyer
03-24-2017, 08:09 AM
I too use a Radio Shack bulk eraser. It is very powerful and does the job.

SwizzyMan
03-25-2017, 04:15 PM
Put in the new crystal and things have improved I believe. The oscillator isnt running at the correct frequency as indicated by the lack of color sync. I dont see nearly as much interference anymore. I did blow out the hv cage with compressed air and moved 1 lead that was somewhat close to a solder joint. I'm not sure if I should adjust L127. Fine tuning isnt able to lock the color and neither is the color control. I think I may have to adjust L127 (reactance coil). Still have no red. :thumbsdn:

SwizzyMan
03-25-2017, 05:36 PM
14 turns counter-clockwise on L127 made the rolling bars a lot higher, but I still cant get it to lock. I reverted L127 back to its original position. I need to hook up the frequency counter and see what the oscillator is running at.

SwizzyMan
03-25-2017, 06:28 PM
I connected the frequency counter to the oscillator. It measured out at about 3.58MHz which was good. The target frequency is 3.57545 so I went off of that. The lowest I could get the oscillator by turning L127 (reactance coil) was 3.57970 which was plenty off. I think I need to add a cap in parallel with the 270 pf cap on the oscillator tank circuit. Your thoughts?

old_tv_nut
03-25-2017, 08:03 PM
Do you know if the capacitors are OK
C201 2p
C202 120p
C209 6.8p
C203 .01
C213 270

How about the reactance tube itself (6AN8)?

The reactance tube works by amplifying the effect of C201 by the variable gain of the tube.

You can check if the oscillator can be pulled by putting, I don't know for sure, but maybe 100pF, from the plate of the reactance tube to ground. If this can pull the oscillator to a lower frequency, and the reactance tube cannot, the problem is in the reactance tube circuit.

SwizzyMan
03-25-2017, 09:16 PM
Do you know if the capacitors are OK
C201 2p
C202 120p
C209 6.8p
C203 .01
C213 270

How about the reactance tube itself (6AN8)?

The reactance tube works by amplifying the effect of C201 by the variable gain of the tube.

You can check if the oscillator can be pulled by putting, I don't know for sure, but maybe 100pF, from the plate of the reactance tube to ground. If this can pull the oscillator to a lower frequency, and the reactance tube cannot, the problem is in the reactance tube circuit.

I will check the tube first. This is somewhat confusing though because the previous crystal was able to oscillate at the right frequency and maintain color lock until the crystal broke. And after doing some reading around it seems Phil Nelson had this same problem with his 4 and adding a cap in parallel with the tank circuit allowed the correct frequency to be reached.

old_tv_nut
03-25-2017, 11:55 PM
I will check the tube first. This is somewhat confusing though because the previous crystal was able to oscillate at the right frequency and maintain color lock until the crystal broke. And after doing some reading around it seems Phil Nelson had this same problem with his 4 and adding a cap in parallel with the tank circuit allowed the correct frequency to be reached.

I think you are right to try the tube first. If that's not the problem:

A crystal for this circuit is cut to parallel resonate with a certain net amount of capacitance. That is, the crystal is operated above its series resonant frequency, and behaves like a large inductor, and is tuned with a small parallel capacitance. If the tank coil is tuned right on frequency, the net capacitance is supplied by the reactance circuit through the 120 pf C202.
The tank being on the far side of the 6.8 pF, it takes a large change in the tank tuning to change the total parallel capacitance across the crystal. I don't doubt that it worked, but a more direct way might be to put a small cap (5-10 pF) directly across the crystal. This way, the tank doesn't have to be detuned so far to get the required net capacitance. Adding capacitance across the tank means you are detuning it from exact parallel resonance to be capacitive when the oscillator is locked, while I think it is really intended to be more or less exactly parallel resonant for oscillator operation.

Different TV manufacturers may have specified different parallel capacitances, for nominal parallel resonance of the crystal. (probably between 18 pF for Zenith [if i recall correctly] and possibly higher values [maybe up to 32 pf but probably in the 20s] for other manufacturers). So, it's possible the crystal you got is not cut for the net capacitance in this chassis, and some more capacitance is needed. This should come from the reactance circuit, not the tank circuit, which is why you tune the reactance coil to zero beat the oscillator.

SwizzyMan
04-01-2017, 05:50 PM
I tacked on a 5 pf cap across the crystal and I can almost get the oscillator to run at the right frequency. It still wont lock even after 20 turns on the reactance coil. Here is what I could get (note the bars rapidly change color every second but I no longer have the barber pole rainbow.)

old_tv_nut
04-01-2017, 07:59 PM
Ok, now you have a chance to find out what part of the loop is dead.

If you have a scope, connect to the top of C198 (4700). If you don't have a scope, connect a DC voltmeter there. Center the AFC balance control. Tune the oscillator so the color cycles through slowly, and you should see the voltage cycle slowly also, as the phase detector cycles through its full range. I don't know what the normal range is, but it should be at least a few volts variation, maybe +/- 10 from nominal zero at most? [Note that the schematic says the nominal control voltage on the grid of the reactance tube is zero volts, so the phase detector output should vary +/- around zero when it is out of lock.] If there is no variation, then either the burst keyer or the phase detector may be dead. If there is a variation, then your problem is still in the reactance tube or oscillator.

SwizzyMan
04-03-2017, 05:03 PM
I checked voltages and waveforms at C198 which is a .01 in this case since I have the early production run of the chassis. I got about 10 volts on the top side of the .01 and 0 volts at the ground side. I didnt see any variation in voltage when adjusting the reactance coil (provided I adjusted the right coil). Here is the waveform I observed at the top side of this cap. Please note that all these measurements were taken with the chassis on the workbench. So no HV or connection to the CRT at all. Here is what I found.

old_tv_nut
04-03-2017, 06:59 PM
Forget the HV, but is the horizontal running on the workbench? It has to be running in order to get a burst gate pulse. No burst gate, nothing gets to the phase detector, so impossible to tell what's wrong or not.

Also, is the scope set for DC coupling? The variation you are looking for is slow, same rate as the color changing a few times per second, so with your high speed scope setting and DC coupling, you would expect the trace to go up and down a few times a second, in sync with the color phase changing. If the scope is set to AC coupling, you won't see such a slow variation at all.

One more thing - if the color is changing rapidly, the voltmeter may not respond in time, that's why the scope is preferred.

SwizzyMan
04-03-2017, 07:26 PM
Forget the HV, but is the horizontal running on the workbench? It has to be running in order to get a burst gate pulse. No burst gate, nothing gets to the phase detector, so impossible to tell what's wrong or not.

Also, is the scope set for DC coupling? The variation you are looking for is slow, same rate as the color changing a few times per second, so with your high speed scope setting and DC coupling, you would expect the trace to go up and down a few times a second, in sync with the color phase changing. If the scope is set to AC coupling, you won't see such a slow variation at all.

One more thing - if the color is changing rapidly, the voltmeter may not respond in time, that's why the scope is preferred.

Oh duh...horizontal was not running. I will need to make a shorting bar for the yoke socket to get it to turn on. Back to square one. Scope was set on ac. When set on DC the trace disappears (please bear with me im new to scopes).

Electronic M
04-03-2017, 07:41 PM
Got an analog VOM with a d'arsonval meter? That ought to capture the variation.
Dirty secret to taking under-chassis measurements with the chassis in the cabinet: get some clip leads connect one end of a lead to a relevant test point and run the other out from under the chassis to your meter probe and slide the chassis back in the cabinet....That method has saved my bacon on sweep and boost troubleshooting a few times.

Also table model CTC-4s have enough harness length (except maybe HV, but that can be addressed) that you can set the chassis up on the floor behind the cabinet with all the under-chassis exposed...For a console like yours if you can find a sturdy box or some such as high off the ground as the chassis shelf then you should be able to pull it up to the back of the set place the chassis on it and make everything reach/accessible.

SwizzyMan
04-03-2017, 07:46 PM
Got an analog VOM with a d'arsonval meter? That ought to capture the variation.
Dirty secret to taking under-chassis measurements with the chassis in the cabinet: get some clip leads connect one end of a lead to a relevant test point and run the other out from under the chassis to your meter probe....That method has saved my bacon on sweep and boost troubleshooting a few times.

I have a voltohmyst, it needs to be calibrated pretty bad. Havent used it in awhile.

Phil Nelson
04-04-2017, 05:25 PM
find a sturdy box or some suchLike a picnic cooler:

http://antiqueradio.org/art/RCACTC-4LameSetup.jpg

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Tom9589
04-04-2017, 08:19 PM
And the best part is that you can keep your beer cold in the cooler while you work!

kvflyer
04-05-2017, 03:25 AM
And the best part is that you can keep your beer cold in the cooler while you work!

But it will be tough to get at...

SwizzyMan
04-05-2017, 05:44 PM
I do the same thing, but I use a sturdy stool instead of a cooler. Makes everything so much easier for sure!

SwizzyMan
04-11-2017, 06:32 PM
I replaced the CRT with a 21FB that is a bit stronger. It displays a beautiful picture with all colors strong except for red which is weak. This has do to a problem with the circuitry driving the red cathode. I have been tracing back through the circuit and have been finding resistors that have gone off. I think I will tackle this problem before I continue on the color sync issue.

SwizzyMan
05-09-2017, 08:42 PM
Im starting to really think the replacement crystal may be bad since it does have a big dent in the side of it (Must have occurred during shipping) and I cant seem to get the color to lock no matter what I do. With the last crystal I could get the color to lock I believe. I will swap the crystal once I can find one. Work has been slow this whole year and I admit I have been lazy with the restoration of this set and have not worked on it as much as I should have. Summer is coming up soon so I hope to have the set finished by August. Slowly but surely this set is shaping up!

Phil Nelson
05-10-2017, 01:38 AM
Sounds like you're nearing the finish line!

If you have a signal generator and scope, you can do a bench test of the crystal. In my CTC-4 article, scroll to the section titled, "Bench Testing the 3.58-MHz Crystals":

http://antiqueradio.org/RCACTC-4ColorTelevision.htm

Thanks to dtvmcdonald for that tip.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
05-31-2017, 06:32 PM
From what I am gathering, I think the crystal may be bad. I have it setup to be bench tested. I'm not seeing a real big change in amplitude when I get around 3.58. First picture is at 3.58 and second is way down around 1mhz. This is what I believe the change should look like https://antiqueradio.org/art/RCACTC-4BenchTesting3-58MHzCrystalAnimation.gif

SwizzyMan
06-02-2017, 11:14 AM
Any thoughts? I believe the crystal is bad, but I'd like some advice before I go out and buy one.

old_tv_nut
06-02-2017, 12:51 PM
They're cheap - get one or a few
http://www.newark.com/raltron/a-3-579545-18/crystal-3-579545mhz-18pf-hc-49u/dp/96F2798

SwizzyMan
06-02-2017, 10:08 PM
Cant go wrong at 58 cents. Ill pick one up soon and go from there. I now have a whole lot of time to work on the set now. I hope to get it wrapped up by august. :yes:

SwizzyMan
06-27-2017, 10:53 PM
New crystal is in and I can see a bit of improvement. Still cant get color to lock. But I can faintly see color through the rolling bars. Black and white picture is perfect I just cant get this pesky color to lock. I have tried putting caps across the crystal but I cant seem to get the frequency below 3.57900 (with a cap across the crystal). Reading through Phil's article on his 4 reveals that a 100pf cap can be put across L142 I believe. This TV wants to produce color, it is so close! Should I add a cap across L142?

old_tv_nut
06-27-2017, 11:53 PM
... I have tried putting caps across the crystal but I cant seem to get the frequency below 3.57900 (with a cap across the crystal)...

Did you mistype the frequency? 3.57900 is too low - should be 3.579545.

Edit: oops - I see you meant 3.57966 - still high.

old_tv_nut
06-28-2017, 12:03 AM
More C across L142 is easy and worth a try, I think.

SwizzyMan
06-28-2017, 12:03 AM
Did you mistype the frequency? 3.57900 is too low - should be 3.579545.

Edit: oops - I see you meant 3.57966 - still high.

Yes right, my bad. I can get it down from 3.57966 to 3.57900 with a cap across the crystal.

old_tv_nut
06-28-2017, 12:07 AM
What size cap across the crystal? It's probably too big if it pulls it 545 Hz too low. It needs to free run close to correct so the reactance tube and coil can pull it either way.

old_tv_nut
06-28-2017, 12:10 AM
I don't have the alignment procedure, but I imagine at some point you are instructed to tune the reactance coil for zero beat. If you can't make free-running frequency correct, the reactance circuit has little chance to pull it in.

SwizzyMan
06-28-2017, 12:15 AM
What size cap across the crystal? It's probably too big if it pulls it 545 Hz too low. It needs to free run close to correct so the reactance tube and coil can pull it either way.

I seem to be mixing up my results here. What I get with the crystal across the cap is 3.5760. The target is 3.57545. I am not putting the right results here. Let me start over now. The closest I can get the oscillator to run at is 3.5766 without a cap across crystal. With a cap across the crystal I pull about 3.5762 or thereabouts. the capacitor across the crystal does not pull down the frequency much at all. I would venture to guess the cap was maybe 5pf.

old_tv_nut
06-28-2017, 12:53 AM
Are you getting tired? You seem to be missing a 9 this time. I think this time the numbers you meant to type were something like:
crystal across cap: 3.57960
target: 3.579545
without a cap: 3.57966

If that's right, the cap is pulling it 60 Hz, which is a nice amount of pull, so it seems something else is wrong. Which capacitors in the reactance tube section and the 3.58 MHz oscillator have you NOT replaced? Do you know for sure the reactance tube is good? Is the plate voltage 5 volts lower than the B+ supply as the schematic says? Time to look for anything that is not right.

old_tv_nut
06-28-2017, 12:56 AM
By the way, too much capacitance across the crystal will lessen the effect of the reactance tube, so, since you see the frequency being pulled a good amount by the added cap, it may be better to remove it while looking for other causes.

I'm going to bed now, will check in tomorrow to read the latest. Good luck!

SwizzyMan
06-28-2017, 09:48 AM
Are you getting tired? You seem to be missing a 9 this time. I think this time the numbers you meant to type were something like:
crystal across cap: 3.57960
target: 3.579545
without a cap: 3.57966

If that's right, the cap is pulling it 60 Hz, which is a nice amount of pull, so it seems something else is wrong. Which capacitors in the reactance tube section and the 3.58 MHz oscillator have you NOT replaced? Do you know for sure the reactance tube is good? Is the plate voltage 5 volts lower than the B+ supply as the schematic says? Time to look for anything that is not right.

Yeah I was up a bit later than usual last night.. Sorry about that. Your numbers are right just know that the lowest frequency is a bit rounded. To be exact I get about 3.579620 which is a bit higher than 3.579600 but it shouldnt really make much difference. The 6AN8 reactance tube is confirmed good. I'll check the voltage on the plate of the pentode of the 6AN8 next.

SwizzyMan
06-28-2017, 11:24 AM
There must have been some intermittent connection in the socket of the reactance tube because now the color is solidly locked!! Frequency is on the dot! But I do have the wrong colors for sure and the hue/tint control changes the colors but doesnt give me all the right colors. I do know that I can do a touch up by adjusting the coil that is controlled in a way by the hue control (the control seems to act like a variable inductor?). But i think I should do a color temperature setup first. Your thoughts?

Electronic M
06-28-2017, 01:58 PM
You may need to adjust L86 (sams). It sets the relative phase angles of the demodulators...If it is off you will be able to get the red bar red and the blue bar blue but not both at once (and similar problems)... IIRC you have to adjust a slug on top of chassis and a slug under chassis simultaneously with plastic* straight edge alignment screwdrivers (had to do this on my CTC-4). *Metal screw drivers will act like an extension of the slug and your freshly tuned adjustments will de-tune as the metal driver is withdrawn from the transformer can (spoken from experience :stupid: ).

If the color temp is right with the set operating in B&W mode then it is right, and does not need messing with....If turning on the color circuits throws the greyscale color temp off then there are problems in the color circuits causing that.

EDIT: BTW congrats on getting sync! It seems these sets like to get dirty intermittent tube sockets.

SwizzyMan
06-28-2017, 02:10 PM
You may need to adjust L86 (sams). It sets the relative phase angles of the demodulators...If it is off you will be able to get the red bar red and the blue bar blue but not both at once (and similar problems)... IIRC you have to adjust a slug on top of chassis and a slug under chassis simultaneously with plastic straight edge alignment screwdrivers (had to do this on my CTC-4).

If the color temp is right with the set operating in B&W mode then it is right, and does not need messing with....If turning on the color circuits throws the greyscale color temp off then there are problems in the color circuits causing that.

EDIT: BTW congrats on getting sync! It seems these sets like to get dirty intermittent tube sockets.


Glad it was just a matter of intermittent connection then that of a bad part! I'll give your suggestion a try.

SwizzyMan
06-28-2017, 03:54 PM
Either im not adjusting L86 properly or we have a different problem here. After turning both shafts one turn CCW the screen develops a yellowish green tint. And after a turn clockwise it does the same thing. If i turn the slugs individually the top part of the coil seems to have a bigger effect than the bottom portion. What could I be doing wrong?

Electronic M
06-28-2017, 04:29 PM
IIRC (it's been ~4 years since I was working on mine) There maybe some interplay with the tint control. I think there may have been some tinting of gray scale when adjusting those slugs on mine. Also on color sets if the color lock is lost with saturated bars the bars will tend to all turn one color.

Put 86 back how it was, adjust the tint so as many of the bars are as close to the correct color as possible, then try 86 together with the tint control and see if you can get it better.

Also you may have the color level up too high. The first bar should be white IIRC. If you overdrive the color level on some (otherwise perfect) sets the tint of some colors will shift abnormally. Reduce color level till the bars are pastel/faintly colored and readjust.

SwizzyMan
06-28-2017, 04:35 PM
IIRC (it's been ~4 years since I was working on mine) There maybe some interplay with the tint control. I think there may have been some tinting of gray scale when adjusting those slugs on mine. Also on color sets if the color lock is lost with saturated bars the bars will tend to all turn one color.

Put 86 back how it was, adjust the tint so as many of the bars are as close to the correct color as possible, then try 86 together with the tint control and see if you can get it better.

Also you may have the color level up too high. The first bar should be white IIRC. If you overdrive the color level on some (otherwise perfect) sets the tint of some colors will shift abnormally. Reduce color level till the bars are pastel/faintly colored and readjust.

I did have the color turned all the way up. But i did adjust the tint for the best match. The only color that is correct seems to be the red bar which is in the right spot.

Electronic M
06-28-2017, 05:17 PM
What I mean is if you turn the color all the way up one or more bars may independently change tint in the opposite direction of another bar such that there is no setting where all the bars are right....I've seen it before where once color is over driven there is no longer a setting where all bars are right since one or more have wandered off of correct relation to the others.

SwizzyMan
06-28-2017, 05:19 PM
What I mean is if you turn the color all the way up one or more bars may independently change tint in the opposite direction of another bar such that there is no setting where all the bars are right....I've seen it before where once color is over driven there is no longer a setting where all bars are right since one or more have wandered off of correct relation to the others.

Got it. Ill lower it then try adjusting L86

SwizzyMan
06-28-2017, 05:42 PM
After turning down the color a bit and adjusting L86 I finally have pretty much the correct colors! But as you can see there is heavy interference in the picture. What I think Ill do next is inject a video signal from a dvd player directly to the grid of the Audio amp tube and see if that clears up interference so I can narrow down whats causing it. Any thoughts on what could be the cause of the interference? The camera makes the picture look a bit more clear, but in person the interference is heavy.

old_tv_nut
06-28-2017, 05:48 PM
I don't have the SAMS, just the schematic that's on earlytv.org (RCA?). If "L86" on SAMS is the output of the 3.58 MC oscillator (T115 on the earlytv schematic), then you may be killing the oscillator when tuning too far. If all the bars suddenly go to the same greenish hue, that can be an indication that the oscillator stopped running on some chassis (I'm not certain about the CTC4).

Edit: we crossed posts - glad you have it working.

old_tv_nut
06-28-2017, 05:54 PM
I really don't have a firm idea about the interference, but I see what looks like delay line ringing in the video (multiple trailing ghosts). Maybe there could be a bad ground or something that's making the video circuits oscillate (?). Does the interference change when you adjust the contrast?

SwizzyMan
06-28-2017, 07:40 PM
Well I found the source of all the nasty interference. It was my agile modulator! Funny thing is that the interference doesnt really show up in my 7 but does show up a bit in my 5. I hooked the set directly to my cable box and the difference is night and day. Obviously purity and convergence are piss poor, but I'll do convergence later tonight.

SwizzyMan
06-28-2017, 10:02 PM
Convergence on this set couldnt be more confusing. Has anyone here done convergence on a 4 and could you guide me in the right direction? I tried to follow the manual, but it is still rather confusing.:thumbsdn:

BigDavesTV
06-29-2017, 11:50 AM
Wow, nice to see it at this point, congratulations!

Phil Nelson
06-29-2017, 12:43 PM
Convergence on this set couldnt be more confusing. Has anyone here done convergence on a 4 and could you guide me in the right direction? I tried to follow the manual, but it is still rather confusing.:thumbsdn:Your TV is starting to look pretty good. What manual are you using? The most detailed service book is the 91-page RCA service clinic manual. This article has a link to download it:

https://antiqueradio.org/RCACTC-4ColorTelevision.htm

I believe the color setup procedure starts around page 25. Go through it step by step, in the order given (i.e., purity first, then convergence). It's essential to use a pattern generator. The dot pattern is most useful for convergence.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
06-29-2017, 01:51 PM
Thanks for the kind words guys! The set is really shaping up now. But there is still a lot of work to be done both electrically and on the cabinet. Im having custom decals made for the decals located under the knobs. Im debating on whether to refinish it or not. Oh and Phil, I am using the factory RCA manual to go through the setup. I will take a look at the one on your page too. Convergence needs to be done before I can do purity since poor center convergence will make it hard to get good purity. Ill try and figure out convergence soon, but it sure is confusing!

benman94
06-29-2017, 02:02 PM
Try another modulator. I've found direct connection to a Charter cable box (that's who we had out by my folks) to overload the set. I'm wondering if you don't have an AGC issue, or if the Blonder-Tongue wasn't set too high....

Electronic M
06-29-2017, 02:26 PM
Thanks for the kind words guys! The set is really shaping up now. But there is still a lot of work to be done both electrically and on the cabinet. Im having custom decals made for the decals located under the knobs. Im debating on whether to refinish it or not. Oh and Phil, I am using the factory RCA manual to go through the setup. I will take a look at the one on your page too. Convergence needs to be done before I can do purity since poor center convergence will make it hard to get good purity. Ill try and figure out convergence soon, but it sure is confusing!

As soon as you do purity it may throw dynamic and or static convergence off and to an extent vice versa....This will probably be an iterative process, touch up purity, touch up static convergence, rinse and repeat till it is right.

It may be wise to unplug the convergence yoke do the static and purtiy till right then plug it back in and go after the dynamic.....Make sure your H and V size and lin are right before doing the convergence since there will be interplay.

Steve D.
06-29-2017, 02:39 PM
You'll probably be able to achieve good center convergence eventually. Edge convergence, in my experience, may be a little more difficult. If the picture looks good from 7 or 10 feet away and you've been dealing w/the convergence for hours...
Just know when to walk away. Or order up a strait jacket to restrain you from tweaking one more control.:yikes:

-Steve D.

WISCOJIM
06-29-2017, 03:54 PM
Or order up a strait jacket to restrain you from twicking one more control.:yikes:

-Steve D.Yikes is right! http://www.urbandictionary.com/define.php?term=twicking

Steve D.
06-29-2017, 04:50 PM
Yikes is right! http://www.urbandictionary.com/define.php?term=twicking

Alas, My spellcheck let me down. Who knew?
My post has been corrected.


-Steve D.

SwizzyMan
06-29-2017, 06:48 PM
This thing keeps getting better and better! I was able to get decent center convergence with dynamic unplugged. Once I plug in dynamic it throws it off a bit but ill cross that bridge when I need to. But the picture looks a lot better with good center convergence for sure. And look at those colors! :D

Electronic M
06-29-2017, 08:51 PM
Nice work! :thmbsp:

Your making me think about restarting the resto on mine that the move out of the old apartment interrupted.

Bill R
06-29-2017, 08:55 PM
It looks like you have made some good progress. However, you are still off on some of the basics. Do you have the Sam's for it? Sometimes the procedures are easier to follow in the Sam's. First things first, and remember all of them interact with each other. I notice from your last picture that you still do not have the vertical size and height quite right. Those blocks should all be the same size. The key is get the Black and white picture right, then worry about the color picture. I would turn the color off and forget for now. Try to get the linearity right first. Do not unplug the convergence board. Then work on purity, center static convergence, purity, static convergence, purity, static convergence. Repeat as needed until the one dot in the center is perfect. Then you can worry about dynamic convergence. Follow the steps in order and do not skip any. You will probably do it several times. Then recheck purity, and static convergence and tweek as needed and start over. It sounds intimidating, but by the time you run through it a couple of times you will get good at it and the entire thing can be done in less than an hour. Be sure the High voltage is correct, and the focus works properly. You may find it easier if you turn the brightness or contrast down some. You will get sharper lines. If you encounter any problems, make the necessary repair before proceeding. Now, it is time to do the gray scale adjustments. After all this you should have a nearly perfect black and white picture. Now you can turn the color up and start working on the color circuits. If you put any capacitor or part in that was not there originally, remove it. It wasn't necessary when new and shouldn't be necessary now. Be sure and check all the circuit grounds, and tube sockets. They are trouble areas. I would try a color alignment. Follow the steps in order. It is not hard. Usually you will ground a test point to let the oscillator free run and adjust the coil until the bars are stable, or only move very slowly. You will then remove the jumper and if the color oscillator, and bandpass amp are working the color should lock in solid. If not you will need to do some troubleshooting and do it again. Once color locks in it may be wrong so that will be adjusted next. You will center the tint control and adjust the transformers in the demodulator circuit for correct flesh tones and proper tint range. It is a balancing act. Now you should have a good color picture with proper tint range. Notice that unless you are using a vectorscope I have not mentioned any color bars. The early procedures use a keyed rainbow pattern, not the NTSC pattern you are using. You do still have an IF alignment issue since the color does not quite fit the black and white picture. On your color bars you can see it as the intensity of the color bar dropping off near the edge of the bar, or bleeding onto the next bar. Do carefully check the caps and resistors in the IF strip since some could have drifted off value. Replacing the drifted components may fix the problem without doing an alignment. DO NOT attempt this alignment without the proper equipment. You would need a Sweep marker generator, Oscilloscope with demodulator probe, and a bias power supply.
You are making great progress, just remember to try not to get ahead of yourself. You will end up chasing problems that may not really be there.

SwizzyMan
06-29-2017, 09:06 PM
It looks like you have made some good progress. However, you are still off on some of the basics. Do you have the Sam's for it? Sometimes the procedures are easier to follow in the Sam's. First things first, and remember all of them interact with each other. I notice from your last picture that you still do not have the vertical size and height quite right. Those blocks should all be the same size. The key is get the Black and white picture right, then worry about the color picture. I would turn the color off and forget for now. Try to get the linearity right first. Do not unplug the convergence board. Then work on purity, center static convergence, purity, static convergence, purity, static convergence. Repeat as needed until the one dot in the center is perfect. Then you can worry about dynamic convergence. Follow the steps in order and do not skip any. You will probably do it several times. Then recheck purity, and static convergence and tweek as needed and start over. It sounds intimidating, but by the time you run through it a couple of times you will get good at it and the entire thing can be done in less than an hour. Be sure the High voltage is correct, and the focus works properly. You may find it easier if you turn the brightness or contrast down some. You will get sharper lines. If you encounter any problems, make the necessary repair before proceeding. Now, it is time to do the gray scale adjustments. After all this you should have a nearly perfect black and white picture. Now you can turn the color up and start working on the color circuits. If you put any capacitor or part in that was not there originally, remove it. It wasn't necessary when new and shouldn't be necessary now. Be sure and check all the circuit grounds, and tube sockets. They are trouble areas. I would try a color alignment. Follow the steps in order. It is not hard. Usually you will ground a test point to let the oscillator free run and adjust the coil until the bars are stable, or only move very slowly. You will then remove the jumper and if the color oscillator, and bandpass amp are working the color should lock in solid. If not you will need to do some troubleshooting and do it again. Once color locks in it may be wrong so that will be adjusted next. You will center the tint control and adjust the transformers in the demodulator circuit for correct flesh tones and proper tint range. It is a balancing act. Now you should have a good color picture with proper tint range. Notice that unless you are using a vectorscope I have not mentioned any color bars. The early procedures use a keyed rainbow pattern, not the NTSC pattern you are using. You do still have an IF alignment issue since the color does not quite fit the black and white picture. On your color bars you can see it as the intensity of the color bar dropping off near the edge of the bar, or bleeding onto the next bar. Do carefully check the caps and resistors in the IF strip since some could have drifted off value. Replacing the drifted components may fix the problem without doing an alignment. DO NOT attempt this alignment without the proper equipment. You would need a Sweep marker generator, Oscilloscope with demodulator probe, and a bias power supply.
You are making great progress, just remember to try not to get ahead of yourself. You will end up chasing problems that may not really be there.

Thanks you for the detailed instructions. I will do linearity first. The Black and White picture is already pretty solid aside from vertical linearity and height. If push comes to shove with the IF, I can always inject a composite signal into the grid of the video amp tube.

Phil Nelson
06-29-2017, 10:27 PM
If push comes to shove with the IF, I can always inject a composite signal into the grid of the video amp tube.That's what I had hoped, too, but video injection is not as simple on the CTC-4 as in typical BW sets. The last two sections in the article at https://antiqueradio.org/RCACTC-4ColorTelevision.htm discuss this issue.

Executive summary: video injection requires adding a video preamp as described in the 1956 RCA Broadcast News article. I did breadboard such a preamp, but version 1.0 was disappointing and I set the project aside to work on other stuff for a while.

On the positive side, those are pretty true-looking color bars. You are not far from having a very watchable CTC-4. The edge convergence might never be as good as the center convergence, but that's common in early color roundies. Whichever manual you follow, take Bill's advice -- go step by step in the order shown and do not skip steps.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

SwizzyMan
06-29-2017, 10:32 PM
This is the best I can get on height and linearity. As you can see the height isnt quite high enough. I swapped vertical out tubes with a bit of improvement. Hmmm, usually insufficient vertical height would indicate bad filters maybe, but all have been replaced so it must be something else.

SwizzyMan
06-30-2017, 12:12 PM
That's what I had hoped, too, but video injection is not as simple on the CTC-4 as in typical BW sets. The last two sections in the article at https://antiqueradio.org/RCACTC-4ColorTelevision.htm discuss this issue.

Executive summary: video injection requires adding a video preamp as described in the 1956 RCA Broadcast News article. I did breadboard such a preamp, but version 1.0 was disappointing and I set the project aside to work on other stuff for a while.

On the positive side, those are pretty true-looking color bars. You are not far from having a very watchable CTC-4. The edge convergence might never be as good as the center convergence, but that's common in early color roundies. Whichever manual you follow, take Bill's advice -- go step by step in the order shown and do not skip steps.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I had a feeling that it would be a bit more than just injecting a signal into the grid. I originally was under the impression that this was able to be done. Member DaveWM paid a visit to my place and suggested that I should try this. Not sure if he knew that there was more to it than just injecting a direct video source. Or hopefully he was right? He has worked on a couple early color sets so maybe he was on to something?

SwizzyMan
06-30-2017, 02:44 PM
I will be out of town for the 4th until next Wednesday. While I am gone, I will do some reading through the manuals and gather some extra info on the problem areas. Until then stay tuned! Everyone have a happy 4th of July and I'll be back on this set next week! :thmbsp:

Bill R
06-30-2017, 09:56 PM
You likely have some bad capacitors in the vertical stage still. If you could put a circle pattern up from a generator or dvd, you can adjust for a perfect circle then you will see if the raster will fill the screen. Also check the circuit grounds in the vertical output stage. B+ could be a little low. If it is to low the picture will usually pull in horizontally some. Be sure and check the resistors as well. There may be some that have drifted high in value.

SwizzyMan
07-08-2017, 05:34 PM
After leaving no stone unturned in the vertical circuit (which isnt many). I found only one barely out of tolerance resistor a 2.2meg 1/2w coming off G1 of the 6AQ5 vertical amp then goes to ground. Not sure it is too critical and its just barely off spec I mean like less than 1% off spec so I might just leave it. All caps are fine except I did replace a .039 which comes off the plate of the vertical amp and goes to the red cathode of the CRT. The original the maroon drop cap tested OK but I had a cap on hand and replaced it. Dont think it will make the vertical any higher though..

Bill R
07-08-2017, 08:23 PM
After leaving no stone unturned in the vertical circuit (which isnt many). I found only one barely out of tolerance resistor a 2.2meg 1/2w coming off G1 of the 6AQ5 vertical amp then goes to ground. Not sure it is too critical and its just barely off spec I mean like less than 1% off spec so I might just leave it. All caps are fine except I did replace a .039 which comes off the plate of the vertical amp and goes to the red cathode of the CRT. The original the maroon drop cap tested OK but I had a cap on hand and replaced it. Dont think it will make the vertical any higher though..

I would probably replace that resistor. Also how does the B+ look? 380V? Also I might replace c169 even if it tested good. Also don't rule out a weak tube.

miniman82
07-09-2017, 11:00 AM
Lack of height is nearly always drifted dropping resistors coming from B+boost so look at R119, the height pot, R117 and R118. If they all spec out, lower the value of R119 till the picture fills the screen. If I had to guess our vertical output transformers are going soft slowly, only solution is to feed them more voltage. Those are Sams resistors BTW.

SwizzyMan
07-09-2017, 05:57 PM
Lack of height is nearly always drifted dropping resistors coming from B+boost so look at R119, the height pot, R117 and R118. If they all spec out, lower the value of R119 till the picture fills the screen. If I had to guess our vertical output transformers are going soft slowly, only solution is to feed them more voltage. Those are Sams resistors BTW.

All check out fine. R117 is just barely in spec but I don't think that this will be an issue. B+ is 399 but know that I havent added any dropping resistors to the 4007 diodes in place of the seleniums so that should explain the high B+. Looks like I need to experiment with different values for R119.

old_tv_nut
07-09-2017, 08:20 PM
Hmm... can you measure the high voltage? If it's high, it may reduce the scan size.

Also, if you have a variac, try adjusting the line voltage.

SwizzyMan
07-10-2017, 12:57 PM
Hmm... can you measure the high voltage? If it's high, it may reduce the scan size.

Also, if you have a variac, try adjusting the line voltage.

Now that you mention it. I have been running the set off my PR57 and when the set is at full operation it does drag the line voltage down about maybe 5 volts. I never thought of adjusting the line voltage after the set has warmed up. This may be the source of my lack of height.

SwizzyMan
07-10-2017, 05:36 PM
Great, now I have even less height and now fold over! :dammit: Looks like I need to retrace my steps here. All I did was replace a cap. I did clip the leg of a few resistors and soldered them back in. I will start by checking my connections on the resistors and cap.

old_coot88
07-10-2017, 09:04 PM
I would run the vert. hold stop-to-stop before diving into it again. It may be locking at an odd sweep rate.

Also, on the line voltage issue, measure the heater voltage. If it's running signifigantly above or below the nominal 6.3 VAC, it'll tell you whether the line voltage is kosher or not.

SwizzyMan
07-10-2017, 09:12 PM
I would run the vert. hold stop-to-stop before diving into it again. It may be locking at an odd sweep rate.

Good thing I traced my work back because I forgot to solder a cap back in circuit. All is fine now. Linearity isnt great but I got it as best as I can. I still think I might lower the value of r119.

SwizzyMan
08-14-2017, 04:34 PM
I have been working on solving a ghosting issue in the picture. Checking resistors on the IF board only revealed 2 out of tolerance resistors. Two 68 ohms coming off the cathode of the 6az8 IF tubes then to ground. Next thing I suspected was the 1n60, but it tests fine on the diode test. Should I still replace it? I need to check around the video amp tubes now.

SwizzyMan
08-14-2017, 05:33 PM
Found an open inductor on the video out tube. L72 on sams 180 Microhenry 9.5ohm. Is this an appropriate replacement? http://www.mouser.com/ProductDetail/Bourns/78F181J-RC/?qs=sGAEpiMZZMsg%252by3WlYCkU69%252bjvm3I6PyJGo%2f 1lu29zY%3d

old_tv_nut
08-14-2017, 08:29 PM
Found an open inductor on the video out tube. L72 on sams 180 Microhenry 9.5ohm. Is this an appropriate replacement? http://www.mouser.com/ProductDetail/Bourns/78F181J-RC/?qs=sGAEpiMZZMsg%252by3WlYCkU69%252bjvm3I6PyJGo%2f 1lu29zY%3d

Looks like it should work fine.

old_tv_nut
08-14-2017, 08:35 PM
Did you check L71 and R68 also?

Edit: also R69, L70, and the contrast control - these are all things that load the input or output of the delay line and need to match the impedance properly to prevent echos.

SwizzyMan
08-14-2017, 09:11 PM
Did you check L71 and R68 also?

Edit: also R69, L70, and the contrast control - these are all things that load the input or output of the delay line and need to match the impedance properly to prevent echos.

Everything tests fine except for maybe the contrast control. It reads 21ohms at full clockwise and about 1k at full counter-clockwise. I dont think that is right.

old_tv_nut
08-14-2017, 10:08 PM
You didn't say which terminals of the contrast you are connected to, but if you don't disconnect one end, you will read a bunch of other things in parallel, particularly the delay line and its 1.2K input resistor. So, the 1K reading is probably normal or close to it for an in-circuit reading. I would just wait to see what the replacement coil does for your ghosting, rather than disconnecting things unnecessarily.

SwizzyMan
08-15-2017, 05:30 PM
Just ordered new coils and resistors. Found another coil that was bad L94 that read about 1 meg when it should be 27 ohm.

timmy
08-15-2017, 06:34 PM
Wow that set is going to be better then originally new once it's done, lots of troubleshooting. Looking good keep at it . :thmbsp:

old_coot88
08-15-2017, 07:04 PM
I have been working on solving a ghosting issue in the picture.
By ghosting, do you mean ringing (parasitic amplitude ripples tagging after fine detail in the pic)? If so, try subbing the last IF tube if you haven't already. It can cause ringing even if it tests good on a tester.

SwizzyMan
08-15-2017, 08:56 PM
By ghosting, do you mean ringing (parasitic amplitude ripples tagging after fine detail in the pic)? If so, try subbing the last IF tube if you haven't already. It can cause ringing even if it tests good on a tester.

Yes. I believe I did try subbing that tube with no difference.